Aromatic amine derivative and organic electroluminescence device

ABSTRACT

An aromatic amine derivative having a specific structure. An organic electroluminescence device which is composed of one or more organic thin film layers sandwiched between a cathode and an anode, wherein at least one of the organic thin film layers, especially a hole transporting layer, contains the aromatic amine derivative. The aromatic amine derivative has at least one substituted or unsubstituted dibenzofuran skeleton and at least one substituted or unsubstituted terphenylene skeleton. Because the molecules in the aromatic amine derivate hardly crystallize, organic electroluminescence devices improving their production yield and having prolonged lifetime are provided.

This is a continuation application of U.S. application Ser. No.12/428,554, filed Apr. 23, 2009.

TECHNICAL FIELD

The present invention relates to an aromatic amine derivative, amaterial for an organic electroluminescence (EL) device, and an organicEL device using the same; and more particularly, to an aromatic aminederivative actualizing the organic EL device capable of lengthening alifetime of the organic EL device by using an aromatic amine derivativehaving a specific structure as a hole injecting material or a holetransporting material.

BACKGROUND ART

An organic EL device is a spontaneous light emitting device whichutilizes a phenomenon that a fluorescent substance emits light by energyof recombination of holes injected from an anode and electrons injectedfrom a cathode when an electric field is applied. Since an organic ELdevice of the laminate type driven under a low electric voltage wasreported by C. W. Tang et al. of Eastman Kodak Company [C. W. Tang andS. A. Vanslyke, Applied Physics Letters, Volume 51, Page 913, 1987],many studies have been conducted on organic EL devices using organicmaterials as the constituting materials. Tang et al. usedtris(8-quinolinolato)aluminum for the light emitting layer and atriphenyldiamine derivative for the hole transporting layer. Advantagesof the laminate structure are that the efficiency of hole injection intothe light emitting layer can be increased, that the efficiency offorming excitons which are formed by blocking and recombining electronsinjected from the cathode can be increased, and that the excitons formedin the light emitting layer can be confined. As the structure of theorganic EL device, a two-layered structure having a hole transporting(injecting) layer and an electron transporting and light emitting layerand a three-layered structure having a hole transporting (injecting)layer, a light emitting layer and an electron transporting (injecting)layer are well known. In order to increase the efficiency ofrecombination of injected holes and electrons in the devices of thelaminate type, the structure of the device and the process for formingthe device have been studied.

Usually, driving or storing the organic EL devices under an environmentof elevated temperatures causes adverse influences such as changes ofluminescent colors, degradation of current efficiency of light emission,increase of their driving voltage, reduction of lifetime in their lightemission, etc. In order for preventing the adverse influences, it wasnecessary to elevate a glass transition temperature (Tg) of a holetransporting material. Accordingly, it is necessary for the holetransporting materials to have many aromatic groups in molecules thereof(for example, aromatic diamine derivatives disclosed in Patent Document1, aromatic fused ring diamine derivatives disclosed in Patent Document2), and usually, structures having 8 to 12 benzene rings are preferablyemployed.

However, in a compound having a symmetrical structure in a molecule,crystallization is liable to occur upon production of the organic ELdevice through the formation of a thin film by using those holetransporting materials. As a result, there arises a problem such asclogging of an outlet of a crucible to be used in vapor deposition or areduction in yields of the organic EL device due to generation ofdefects of the thin film resulting from the crystallization. Inaddition, a compound having a large number of aromatic groups in any oneof molecules thereof generally has a high glass transition temperature(Tg), but has a high sublimation temperature. Accordingly, there arisesa problem in that the lifetime is short, because a phenomenon such asdecomposition at the time of the vapor deposition or the formation of anonuniform deposition film is expected to occur.

Further, although Patent Documents 3 to 5 report about compounds havingdibenzofuran structures, they disclose structures having dibenzofuran asa central skeleton of a diamine compound. Patent Documents 6 to 8disclose about compounds having dibenzofuran structures through an arylgroup in monoamines thereof, however, the compounds do not sufficientlyimprove the performance as the organic EL device.

Also, Patent Documents 9 to 11 report about monoamine compounds having aterphenyl group, however, the compounds are only used forelectrophotographic photoreceptors. Although Patent Documents 12 to 14disclose about usages as materials for the organic EL device, thematerials do not sufficiently improve the performance as the organic ELdevice.

As mentioned above, there are many reports about the organic EL deviceswith prolonged lifetime. However, the lifetime is still insufficient.Accordingly, development of an organic EL device having a more superiorperformance has been eagerly desired.

-   Patent Document 1: U.S. Pat. No. 4,720,432-   Patent Document 2: U.S. Pat. No. 5,061,569-   Patent Document 3: JP 2005-112765A-   Patent Document 4: JP 11-111460A-   Patent Document 5: WO 2006/122630-   Patent Document 6: WO 2006/128800-   Patent Document 7: JP 2006-151844A-   Patent Document 8: JP 2008-021687A-   Patent Document 9: JP 2-134643A-   Patent Document 10: JP 2-190862A-   Patent Document 11: JP 3-118548A-   Patent Document 12: JP 6-228062A-   Patent Document 13: JP 2001-196183A-   Patent Document 14: JP 2006-352088A

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

The present invention has been made to overcome the above problems andhas an object of providing an organic EL device with a prolongedlifetime, and an object of providing an aromatic amine derivativeactualizing the organic EL device.

Means for Solving the Problem

The inventors of the present invention have made extensive studies witha view toward achieving the above-mentioned object. As a result, theinventors have found that the above-mentioned problems can be solved byusing a novel aromatic amine derivative having a specific substituent asa material for an organic EL device, and particularly, as a holeinjecting material or a hole transporting material. It was also foundthat there is preferred an amino group substituted with an aryl grouphaving a dibenzofuran structure and an aryl group having a terphenylstructure as an amine unit having specific substituent.

Further, it has been found that the amine unit shows a smallintermolecular interaction because of the steric hindrance thereof,thereby preventing the crystallization, improving the yield in producingorganic EL devices. It has been also found that presence of terphenylgroup being superior in reduction stability improves the reductionstability of the molecules thereby prolonging the lifetime in theorganic EL devices obtained. Especially, it has been found thatremarkable effects of prolonging the lifetime is obtainable by combiningthe derivative with an EL device emitting blue light. The presentinvention has been accomplished on the basis of the above findings.

Namely, the present invention provides:

(I) An aromatic amine derivative represented by the following generalformula (1).

wherein at least one group among Ar¹ to Ar³ is represented by thefollowing general formula (2):

wherein R¹ and R² each independently represents a substituted orunsubstituted aryl group having the number of carbon atoms of 6 to 50forming the aromatic ring, or a substituted or unsubstituted alkyl grouphaving carbon atoms of 1 to 50; “a” represents an integer of 0 to 4, “b”represents an integer of 0 to 3, and “c” represents an integer of 1 to3; plural R¹'s or R²'s together may be bonded to each other to form asaturated or unsaturated, five- or six-membered ring structure which maybe substituted; Ar⁴ represents a substituted or unsubstituted arylenegroup having the number of carbon atoms of 6 to 50 forming the aromaticring, or a substituted or unsubstituted fluonylene group.

In the general formula (1), at least one of Ar¹ to Ar³ is represented bythe following general formula (3):

wherein R³ to R⁵ are each independently selected from the same groups asthe above R¹; “e” and “1” each independently represents an integer of 0to 4, and “g” represents an integer of 0 to 5; plural R³'s, R⁴'s, orR⁵'s together may be bonded to each other to form a saturated orunsaturated, five- or six-membered ring structure which may besubstituted.

In the general formula (1), one of Ar¹ to Ar³ which is represented byneither the general formula (2) nor the general formula (3) isindependently represented by a substituted or unsubstituted aryl grouphaving the number of carbon atoms of 6 to 50 forming the aromatic ringwith the proviso that it does not include the structure of the generalformula (3);

(II) The aromatic amine derivative as described in the above (I),wherein Ar⁴ is represented by any one of the following general formula(4) or (5):

wherein R⁶'s each independently represents a substituted orunsubstituted aryl group having the number of carbon atoms of 6 to 50forming the aromatic ring, or a substituted or unsubstituted alkyl grouphaving 1 to 50 carbon atoms respectively, “d1” represents an integer of0 to 4, “d2” represents an integer of 0 to 3; and plural R⁶'s on thesame benzene rings or R⁶'s on 2 neighboring benzene rings together maybe bonded to each other to form a saturated or unsaturated, five- orsix-membered ring structure which may be substituted;

(III) The aromatic amine derivative as described in the above (I),wherein Ar⁴ is represented by the following general formula (6):

wherein R⁷'s each independently represents a substituted orunsubstituted aryl group having the number of carbon atoms of 6 to 50forming the aromatic ring, or a substituted or unsubstituted alkyl grouphaving 1 to 50 carbon atoms respectively, and “d3” represents an integerof 0 to 4;

(IV) The aromatic amine derivative as described in the above (I),wherein the above general formula (3) is represented by any one of thefollowing general formula (7), (8) or (9):

wherein R³ to R⁵ and “e” to “g” are the same as those in the abovegeneral formula (3);

(V) The aromatic amine derivative as described in the above (1), whereinone group among the above Ar¹ to Ar³ is represented by the above generalformula (2); and two groups among the above Ar¹ to Ar³ are representedby the above general formula (3);(VI) The aromatic amine derivative as described in the above (1),wherein two groups among the above Ar¹ to Ar³ are represented by theabove general formula (2); and one group among the above Ar¹ to Ar³ isrepresented by the above general formula (3);(VII) The aromatic amine derivative as described in the above (1),wherein one group among the above Ar¹ to Ar³ is represented by thegeneral formula (2); at the same time, Ar⁴ in the general formula (2) isrepresented by the above general formula (4), (5) or (6), and two groupsamong the above Ar¹ to Ar³ are each represented by any one of thegeneral formula (7) or (8) respectively;(VIII) The aromatic amine derivative as described in the above (1),wherein two groups among the above Ar¹ to Ar³ are represented by thegeneral formula (2); at the same time, Ar⁴ in the general formula (2) isrepresented by the above general formula (4), (5) or (6), and one groupamong the above Ar¹ to Ar³ is represented by the general formula (7) or(8);(IX) The aromatic amine derivative as described in the above (1),wherein the above general formula (2) has a structure represented by thefollowing general formula (10):

wherein R¹, R², Ar⁴, “a”, “b” and “c” are the same as the abovedefinition;

(X) The aromatic amine derivative as described in the above (1), whereinone group among the above Ar¹ to Ar³ is represented by the generalformula (2); and two groups among the above Ar¹ to Ar³ are eachrepresented by any one of the general formula (7) or (8) respectively;(XI) The aromatic amine derivative as described in the above (1),wherein two groups among the above Ar¹ to Ar³ are represented by thegeneral formula (2); and one group among the above Ar¹ to Ar³ isrepresented by any one of the general formula (7) or (8);(XII) The aromatic amine derivative as described in the above (I),wherein the aromatic amine derivative is used as a material for organicelectroluminescence devices;(XIII) The aromatic amine derivative as described in the above (I),wherein the aromatic amine derivative is used as a hole injectingmaterial or a hole transporting material;(XIV) An organic electroluminescence device which is composed of one ormore organic thin film layers including at least one light emittinglayer sandwiched between a cathode and an anode, wherein at least one ofthe organic thin film layers contains the aromatic amine derivativedescribed in the above (I) singly or as mixture component thereof;(XV) The organic electroluminescence device as described in the above(XIV), wherein the organic thin film layer has a hole injecting layer ora hole transporting layer, and the hole injecting layer or the holetransporting layer contains the aromatic amine derivative described inthe above (I);(XVI) The organic electroluminescence device as described in the above(XIV), wherein the light emitting layer contains at least one ofstyrylamine and arylamine; and(XVII) The organic electroluminescence device as described in the above(XIV), which emits blue light.

EFFECT BY THE INVENTION

The aromatic amine derivative of the present invention hardly causes thecrystallization of a molecule and further, it improves yields uponproduction of the organic EL device, and contributes to prolong thelifetime of the organic EL devices.

BEST MODE TO CARRY OUT THE INVENTION

In the general formula (1), at least one of Ar¹ to Ar³ is represented bythe above general formula (2).

R¹ and R² in the general formula (2) each independently represents asubstituted or unsubstituted aryl group having the number of carbonatoms of 6 to 50 forming the aromatic ring, preferably 6 to 20, or asubstituted or unsubstituted alkyl group having 1 to 50, preferably 1 to20 carbon atoms; “a” represents an integer of 0 to 4, preferably 0 or 1,and further preferably 0; “b” represents an integer of 0 to 3,preferably 0 or 1, and further preferably 0; and “c” represents aninteger of 1 to 3.

Specific examples of the aryl group include a phenyl group, a naphthylgroup, a phenanthryl group, a crycenyl group, a benzphenanthryl group, aterphenyl group, a benzanthranyl group, a benzo crycenyl group, abiphenyl group, a naphthacenyl group, an anthranyl group, a pentacenylgroup, a picenyl group, a pentaphenyl group, etc.

Specific examples of the alkyl group include a methyl group, an ethylgroup, an isopropyl group, an n-propyl group, a sec-butyl group, atert-butyl group, a pentyl group, a hexyl group, etc.

Examples of the substituent in the aryl group and the alkyl groupinclude an aryl group having the number of carbon atoms of 6 to 50(preferably 6 to 20) forming the aromatic ring (specifically a phenylgroup, a naphthyl group, a phenanthryl group, a crycenyl group,benzphenanthryl group, a terphenyl group, a benz anthranyl group, abenzo crycenyl group, a biphenyl group, a naphthacenyl group, ananthranyl group, a pentacenyl group, a pycenyl group) a substituted orunsubstituted alkyl group having 1 to 50 (preferably 1 to 20) carbonatoms (specifically a methyl group, an ethyl group, an isopropyl group,an n-propyl group, a sec-butyl group, a tert-butyl group, a pentylgroup, a hexyl group), a fluorine atom, a silyl group whose alkyl groupor aryl group is substituted (a trimethylsilyl group, a triethylsilylgroup, a triphenylsilyl group, a tert-butyldimethylsilyl group), etc.

In the general formula (2), plural R¹'s or R²'s together may be bondedto each other to form a saturated or unsaturated, five- or six-memberedring structure which may be substituted. Specific examples of the ringstructure formed by the substituent R¹'s or R²'s in the dibenzofuranstructure being bonded each other [a constitutional section made byremoving (Ar⁴)c unit from the general formula (2)] are as follows:

Ar⁴ represents a substituted or unsubstituted arylene group having thenumber of carbon atoms of 6 to 50 forming the aromatic ring, preferably6 to 20, or a substituted or unsubstituted fluonylene group.

Specific examples of the arylene group include a phenylene group, anaphthylene group, a biphenylene group, a terphenylene group, aphenanthrene group, a triphenylene group, an anthranylene group, apentacenylene group, a perilenylene group, a picenylene group, apyrenylene group, a pentaphenylene group, 9,9-dimethylfluonylene group,9,9-diphenyl fluonylene group and the following compounds, etc.

Examples of the substituent in the arylene group or the fluonylene groupinclude the same examples as the substituent in the aryl group or thealkyl group.

Especially, it is preferable to be any one of the phenylene group or the9,9-dimethylfluonylene group represented by the above general formula(4), (5) or (6).

R⁶ and R⁷ in the above general formula (4), (5) or (6) eachindependently represents a substituted or unsubstituted aryl grouphaving the number of carbon atoms of 6 to 50 forming the aromatic ring,preferably 6 to 20, or a substituted or unsubstituted alkyl group havingcarbon atoms of 1 to 50, preferably 1 to 20; “d1” represents an integerof 0 to 4, preferably 0 to 2; “d2” independently represents an integerof 0 to 3; and “d3” independently represents an integer of 0 to 4,preferably 0 to 2. Plural R⁶'s and plural R⁷'s on the same benzene ringsor R6's and R7's on the neighboring benzene rings together may be bondedto each other to form a saturated or unsaturated, five- or six-memberedring structure which may be substituted; and c representing the numberof Ar⁴ is preferably 1 or 2.

Specific examples of the aryl group and the alkyl group in R⁶ and R⁷,and examples of the substituent that can be bonded with the aryl groupor the alkyl group are the same as those mentioned about the foregoingR¹ and R².

In the general formula (1), at least one of Ar¹ to Ar³ is represented bythe above general formula (3).

In the general formula (3), R³ to R⁵ are each independently selectedfrom the same groups as the above R¹. The substituent which can bebonded to the aryl group or alkyl group is selected from the same groupsas the above R¹; “e” and “f” each independently represents an integer of0 to 4, preferably 0 or 1, and further preferably 0; “g” represents aninteger of 0 to 5, preferably 0 or 1, and further preferably 0. PluralR³'s, R⁴'s or R⁵'s together may be bonded to each other to form asaturated or unsaturated, five- or six-membered ring structure which maybe substituted. R³, R⁴ and R⁵ may be bonded to each other to form asaturated or unsaturated, five- or six-membered ring structure which maybe substituted. Preferred specific examples of the general formula (3)is the case where R³, R⁴ and R⁵ do not form a ring, or the case where R³and R⁴ become a bonding group forming five-membered ring; in otherwords, those with a structure in which a phenyl group or a naphthylgroup is bonded to the para position of 9,9-dimethylfluonylene group.Another example is the case where R⁴ and R⁵ become a bonding groupforming five-membered ring, in other words, those with a structure inwhich 9,9-dimethylfluonylene group is bonded to the para position of aphenyl group or a naphthyl group.

When Ar⁴ is represented by the general formula (4), (5) or (6), it ispreferable that the general formula (3) is represented by any one of thegeneral formulae (7) to (9).

In the general formulae (7) to (9), R³ to R⁵ are each independentlyselected from the same groups as the above R¹ and R² respectively. Thesubstituent which can be bonded to the aryl group or alkyl group isselected from the same groups as the above R¹; “e” and “f” eachindependently represents an integer of 0 to 4, preferably 0 or 1, andfurther preferably 0; “g” represents an integer of 0 to 5, preferably 0or 1, and further preferably 0. R³, R⁴ and R⁵ may be bonded to eachother to form a saturated or unsaturated, five- or six-membered ringstructure which may be substituted.

In the general formula (1), any one of Ar¹ to Ar³ which is representedby neither the general formula (2) nor the general formula (3) is eachindependently represented by a substituted or unsubstituted aryl grouphaving the number of carbon atoms of 6 to 50 forming the aromatic ring,preferably 6 to 20. Specific examples of the aryl group are the same asthose particularized about the above R¹ and R². Preferred specificexamples include a biphenyl group, a naphthyl group and a phenanthrylgroup.

The aromatic amine derivatives wherein at least one group among theabove Ar¹ to Ar³ is represented by the general formula (2), and thosewhich are not represented by the general formula (2) are represented bythe general formula (3) are preferable.

Further, there are preferred the aromatic amine derivatives wherein atleast one group among the above Ar¹ to Ar³ is represented by the generalformula (2), Ar⁴ in the general formula (2) is represented by thegeneral formula (4), (5) or (6), and those remained among the above Ar¹to Ar³ are represented by any one of the general formulae (7) to (9).

Also, there are preferred the aromatic amine derivatives wherein the onegroup among the above Ar¹ to Ar³ is represented by the general formula(2), Ar⁴ in the general formula (2) is represented by any one of thegeneral formulae (4), (5) or (6); and the two groups among the above Ar¹to Ar³ are represented by any one of the general formulae (7) to (9).

Still further, there are preferred the aromatic amine derivative whereinthe two groups among the above Ar¹ to Ar³ are represented by the generalformula (2), Ar4 in the general formula (2) is represented by any one ofthe general formulae (4), (5) and (6); and the one group among the aboveAr¹ to Ar³ is represented by any one of the general formulae (7) to (9).

Furthermore, among the aromatic amine derivative represented by theabove general formula (1), the following embodiments are alsopreferable:

(a) The aromatic amine derivative wherein the above general formula (2)is represented by the foregoing general formula (10). [R¹, R², Ar⁴, “a”,“b”, and “c” in the general formula (10) are the same as those in thegeneral formula (2)](b) The aromatic amine derivative wherein one group among the above Ar¹to Ar³ is represented by the above general formula (2); and two groupsamong the above Ar¹ to Ar³ are each represented by any one of the abovegeneral formula (7) or (8) respectively.(c) The aromatic amine derivative wherein two groups among the above Ar¹to Ar³ are represented by the above general formula (2); and one groupamong the above Ar¹ to Ar³ is represented by any one of the abovegeneral formula (7) or (8).

The aromatic amine derivative of the present invention represented bythe general formula (1) can be synthesized, for example, by thefollowing reaction.

At first, by allowing the compound [e.g., dibenzofuran-4-boronic acidand 4-iodobromobenzene] which generates the structure represented by thegeneral formula (2) to react among the aqueous solution of a solvent[e.g., toluene] and alkaline compound [e.g., sodium carbonate] under thepresence of a catalyst [e.g., tetrakis(triphenylphosphine) palladium(0)]at the temperature of 50 to 150° C., Intermediate X is synthesized. Itis preferable that the reaction is performed under the atmosphere of aninert gas such as argon.

On the other hand, after allowing the halide [e.g., 4-bromo-p-terphenyl]which generates the structure represented by the general formula (3),and a compound which generates an amino group (a compound whichgenerates a substituted or unsubstituted aryl group having 6 to 50 ringforming carbon atoms may be included) [e.g., benzamide] to react eachother in a solvent [e.g., xylene] at the temperature of 50 to 250° C.and under the presence of a catalyst (metal halide such as copper iodideand amine such as N,N′-dimethylethylenediamine) and an alkaline material[e.g., potassium carbonate], Intermediate Y is synthesized by allowingthe resultant solution to react among the solvent [e.g., xylene] at thetemperature of 50 to 250° C. and under the presence of an alkalinematerial [e.g., potassium hydroxide] and water. It is preferable thatthe reaction is performed under the atmosphere of an inert gas such asargon.

Then, by allowing Intermediate X and Intermediate Y to react each otheramong a solvent (e.g. dehydrated toluene) at the temperature of 0 to150° C. under the presence of a catalyst (e.g. t-butoxy sodium andtris(dibenzylideneacetone) dipalladium (0), the aromatic aminederivative of the present invention can be synthesized. It is preferablethat the reaction is performed under the atmosphere of an inert gas suchas argon.

After completing the reaction, cooling the reaction product down to theroom temperature, adding water to the reaction product and filtering it,extracting the filtrate with solvent such as toluene or so, drying itusing a desiccant such as sulfuric anhydride magnesium or so, removingthe solvent and condensing under reduced pressure, column refining thecrude product, re-crystallizing with solvent such as toluene or so, andseparating with filtration, followed by drying provides a purifiedaromatic amine derivative of the present invention.

For the purpose of introducing a substituted or unsubstituted aryl grouphaving 6 to 50 ring forming carbon atoms of neither the general formula(2) nor the general formula (3) into the aromatic amine derivativerepresented by the general formula (1), it is suitable that whenIntermediate X and Intermediate Y are allowed to react each other, orwhen Intermediate Y is synthesized, a reacting content ratio iscontrolled and a halide (e.g., 1-bromonaphthalene) of the substituted orunsubstituted aryl group having 6 to 50 to 20 ring forming carbon atomsof neither the general formula (2) nor the general formula (3) isallowed to react and to be introduced similarly and sequentially. (Forexample, after allowing benzamide and 4-bromo-p-terphenyl to react inmass ratio of 1:1 each other, throwing 1 equivalent of1-bromonaphthalene into the resultant solution and hydrolyzing itprovides Intermediate Y into which the aryl group of the general formula(3) and “the aryl group of neither the general formula (2) nor thegeneral formula (3)” were introduced.)

A halide of the general formula (2), a halide of the general formula(3), and the halide of the substituted or unsubstituted aryl grouphaving 6 to 50 to 20 ring forming carbon atoms of neither the generalformula (2) nor the general formula (3) can be arbitrarily introducedinto Intermediate Y. Also, the aryl group can be introduced singly or inpair, and further, it can be introduced in arbitrary combination.Allowing the resultant amine compound (Intermediate Y) and arbitraryhalide (Intermediate X) to react each other can provide the aimedproduct. These reaction order or combination can be settled consideringthe reactivity, easiness of purification, and so on.

Examples of the general formula wherein Ar¹ to Ar³ in the generalformula (1) are partially or entirely specified further are as follows:

In the above constitutional formula, “h” represents an integer of 1 to3, “i” and “j” each independently represents an integer of 0 to 2, and“h+i+j”=3. R¹ to R⁶, “a” to “c”, “d1” to “d3”, and “e” to “h” are thesame as those described above. Ar^(y) corresponds to any one group amongthe above Ar¹ to Ar^(a).

Specific examples of the aromatic amine derivatives represented by thegeneral formula (1) include the following compounds enumerated below,though not particularly limited thereto.

The aromatic amine derivative represented by the general formula (1) ofthe present invention is preferably used as a material for an organic ELdevice. Also, the aromatic amine derivative represented by the generalformula (1) of the present invention is a light emitting material for anorganic EL device.

The present invention provides an organic electroluminescence devicewhich is composed of one or more organic thin film layers including atleast one light emitting layer between a cathode and an anode, whereinat least one of the organic thin film layers contains any one of thearomatic amine derivative described hereinabove.

In the organic EL device of the present invention, the foregoing holeinjecting layer or the hole transporting layer preferably contains thearomatic amine derivative represented by the above general formula (1).

Following is a description regarding a device structure about theorganic EL device of the present invention.

Typical examples of the construction in the organic EL device of thepresent invention include the following:

(1) An anode/a light emitting layer/a cathode;

(2) An anode/a hole injecting layer/a light emitting layer/a cathode;

(3) An anode/a light emitting layer/an electron injecting layer/acathode;

(4) An anode/a hole injecting layer/a light emitting layer/an electroninjecting layer/a cathode;

(5) An anode/an organic semiconductor layer/a light emitting layer/acathode;

(6) An anode/an organic semiconductor layer/an electron barrier layer/alight emitting layer/a cathode;

(7) An anode/an organic semiconductor layer/a light emitting layer/anadhesion improving layer/a cathode;

(8) An anode/a hole injecting layer/a hole transporting layer/a lightemitting layer/an electron injecting layer/a cathode;

(9) An anode/an insulating layer/a light emitting layer/an insulatinglayer/a cathode;

(10) An anode/an inorganic semiconductor layer/an insulating layer/alight emitting layer/an insulating layer/a cathode;

(11) An anode/an organic semiconductor layer/an insulating layer/a lightemitting layer/an insulating layer/a cathode;

(12) An anode/an insulating layer/a hole injecting layer/a holetransporting layer/a light emitting layer/an insulating layer/a cathode;and

(13) An anode/an insulating layer/a hole injecting layer/a holetransporting layer/a light emitting layer/an electron injecting layer/acathode.

Among the above constructions, construction (8) is usually preferablethough not limited thereto.

Although the material for the organic EL device of the present inventionmay be employed for any of the above organic thin layers in the organicEL devices, it is contained preferably in a light emitting zone, andparticularly preferably in the hole injecting layer or the holetransporting layer. The amount to be contained in the device is selectedfrom 30 to 100% by mole.

The aromatic amine derivative of the present invention is preferablyused as a material for the hole injecting layer or the hole transportinglayer.

The hole injecting layer and hole transporting layer are layers whichhelp the injection of holes into the light emitting layer and transportthe holes to the light emitting region. The layer exhibits a greatmobility of holes and, in general, has an ionization energy as small as5.5 eV or smaller. For the hole injecting and transporting layer, amaterial which transports holes to the light emitting layer at a smallstrength of the electric field is preferable. A material which exhibits,for example, a mobility of holes of at least 10⁻⁴ cm²/V·s underapplication of an electric field of from 10⁴ to 10⁶ V/cm is preferable.The compound of the present invention has a small ionization energy, anda large hole mobility so that it is preferable as the hole transportingmaterial. Further, because it contains a polar group in the moleculethereof, the adhesive property with the anode is excellent and it hardlysuffers influences of cleaning condition about the substrate so that itis preferable as the hole injecting material. These factors conceivablyprolong lifetime of the organic EL device utilizing the presentinvention.

To form the hole injecting layer and the hole transporting layer, a thinfilm may be formed from the aromatic amine derivative of the presentinvention in accordance with a well-known process such as the vacuumvapor deposition process, the spin coating process, the casting processand the LB process. Although the thickness of the hole injecting layerand the hole transporting layer is not particularly limited, thethickness is usually from 5 nm to 5 μm. The hole injecting layer or thehole transporting layer may be a single layer made of one or more kindsof materials mentioned above or may be laminated with another holeinjecting layer or the hole transporting layer made of a differentmaterial, as long as the hole injecting layer or the hole transportinglayer contains the aromatic amine derivative of the present invention inthe hole transporting zone thereof.

An organic semiconductor layer is a layer which assists to inject theholes or to inject the electrons into the light emitting layer, and itis preferable for the organic semiconductor layer to have a conductanceof 10⁻¹⁰ S/cm or greater. Examples of the materials for the organicsemiconductor layer include electrically conductive oligomers such as anoligomer having thiophene and an oligomer having arylamine disclosed inJP 8-193191A; and electrically conductive dendrimers such as a dendrimercontaining an aryl amine dendrimer.

The organic EL device of the present invention is prepared on alight-transmissive substrate. Here, the light-transmissive substrate isthe substrate which supports the organic EL device. It is preferablethat the light-transmissive substrate have a transmittance of light of50% or higher in the visible region of 400 to 700 nm and be flat andsmooth.

Preferred examples of the light-transmissive substrate include glassplates and polymer plates. Specific examples of the glass plate includesoda ash glass, glass containing barium and strontium, lead glass,aluminosilicate glass, borosilicate glass, barium borosilicate glass andquartz. Specific examples of the synthetic resin plate include a platemade of polycarbonate resins, acrylic resins, polyethylene telephthalateresins, polyether sulfide resins and polysulfone resins.

The anode in the organic EL device of the present invention has afunction of injecting holes into a hole transporting layer or a lightemitting layer, and it is effective that the anode has a work functionof 4.5 eV or greater. Specific examples of the material for the anodeused in the present invention include indium tin oxide (ITO), mixture ofindium oxide and zinc oxide (IZO^(R)), mixture of ITO and cerium oxide(ITCO), mixture of IZO^(R) and cerium oxide (IZCO), mixture of indiumoxide and cerium oxide (ICO), mixture of zinc oxide and aluminum oxide(AZO), tin oxide (NESA), gold, silver, platinum, and copper, etc.

The anode can be prepared by forming a thin film of the electrodematerials in accordance with a process such as the vapor depositionprocess and the sputtering process.

When the light emitted from the light emitting layer is obtained throughthe anode, it is preferable that the anode has a transmittance of theemitted light greater than 10%. It is also preferable that the sheetresistivity of the anode is several hundreds Ω/□ or smaller. Thethickness of the anode is, in general, selected in the range of 10 nm to1 μm and preferably in the range of 10 to 200 nm although the preferablerange may be different depending on the material to be used.

For the cathode, a material such as a metal, an alloy, an electricallyconductive compound, or a mixture of the materials which has a smallwork function (4 eV or smaller) is used as an electrode material.Specific examples of the electrode substance include sodium,sodium-potassium alloy, magnesium, lithium, magnesium-silver alloy,aluminum/aluminum oxide, Al/Li₂O, Al/LiO, Al/LiF, aluminum-lithiumalloy, indium, rare earth metal, etc.

The cathode can be prepared by forming a thin film of the electrodematerial described above in accordance with a process such as the vapordeposition process and the sputtering process.

When the light emitted from the light emitting layer is taken out of thecathode, it is preferable that the cathode has a transmittance ofgreater than 10% to the emitted light. It is also preferable that thesheet resistivity of the cathode is several hundreds Ω/□ or smaller andthe thickness of the cathode is, usually selected from 10 nm to 1 μm andpreferably from 50 to 200 nm.

In general, the organic EL device tends to form defects in pixels due toleak and short circuit since an electric field is applied to ultra-thinfilms. To prevent the defects, an insulating layer made of anelectrically insulating thin film may be inserted between the pair ofelectrodes.

Examples of the material for the insulating layer include aluminumoxide, lithium fluoride, lithium oxide, cesium fluoride, cesium oxide,magnesium oxide, magnesium fluoride, calcium oxide, calcium fluoride,aluminum nitride, titanium oxide, silicon oxide, germanium oxide,silicon nitride, boron nitride, molybdenum oxide, ruthenium oxide andvanadium oxide. Mixtures and laminates of the above compounds can alsobe employed.

In the organic EL device of the present invention, the light emittinglayer combines the following functions:

(i) The injecting function: the function of injecting holes from theanode or the hole injecting layer and injecting electrons from thecathode or the electron injecting layer when an electric field isapplied;(ii) The transporting function: the function of transporting theinjected charges (electrons and holes) by the force of the electricfield; and(iii) The light emitting function: the function of providing the fieldfor recombination of electrons and holes and promote the recombinationto emit light.

As the process for forming the light emitting layer, a well-knownprocess such as the vapor deposition process, the spin coating processand the LB process can be employed. It is particularly preferable forthe light emitting layer to be a molecular deposit film. The moleculardeposit film is a thin film formed by the deposition of a materialcompound in the gas phase or a thin film formed by the solidification ofa material compound in a solution or liquid phase. In general, themolecular deposit film can be distinguished from the thin film formed inaccordance with the LB process (the molecular accumulation film) basedon the differences in the aggregation structure and higher orderstructures and functional differences caused by these structuraldifferences.

In addition, as disclosed in JP 57-51781A, the light emitting layer canalso be formed by dissolving a binder such as a resin and the materialcompounds into a solvent to prepare a solution, followed by forming athin film from the prepared solution in accordance with the spin coatingprocess or the like.

The thickness of the light emitting layer is preferably selected in therange of from 5 to 50 nm, more preferably in the range of from 7 to 50nm and the most preferably in the range of from 10 to 50 nm. It isresulted in difficult to form the light emitting layer and to controlchromaticity thereof when the thickness is thinner than 5 nm, and it maybe resulted in possibility of elevating driving voltage when it exceeds50 nm.

Examples of the material which can be used in the light emitting layerare not particularly limited and include polycyclic aromatic compoundsuch as an anthracene compound, a phenanthrene compound, a fluoranthenecompound, a tetracene compound, a triphenylene compound, a chrysenecompound, a pyrene compound, a coronene compound, a perylene compound, aphthaloperylene compound, a naphthaloperylene compound, a naphthacenecompound, and a pentacene compound; oxadiazole, bisbenzoxazoline,bisstyryl, cyclopentadiene, quinoline metal complexes,tris(8-hydroxyquinolinato) aluminum complexes,tris(4-methyl-8-quinolinato) aluminum complexes,tris(5-phenyl-8-quinolinato) aluminum complexes, aminoquinoline metalcomplexes, benzoquinoline metal complexes, tri-(p-terphenyl-4-yl)amine,1-aryl-2,5-di(2-thienyl)pyrrole derivatives, pyran, quinacridone,rubrene, distyrylbenzene derivatives, distyrylarylene derivatives,porphyrin derivatives, stilbene derivatives, pyrazoline derivatives,coumarin based dyes, pyran based dyes, phthalocyanine based dyes,naphthalocyanine based dyes, croconium based dyes, sqarium based dyes,oxo benzanthracene based dyes, fluorescein based dyes, rhodamine baseddyes, pyrylium based dyes, perylene based dyes, stilbene based dyes,polythiophene based dyes; or rare earth complex based fluorescentsubstances, rare earth-based phosphorescent light emitting complexes(e.g., Ir complexes) and polymer materials like electrically conductivepolymers such as polyvinylcarbazole, polysilane, polyethylenedioxidethiophene (PEDOT). These may be used alone, or, alternatively,used as a mixture of two or more kinds thereof.

Preferable materials to be used for the light emitting layer of thepresent invention include compounds represented by the following generalformulae (51) to (57).

In the anthrathene derivative represented by the formula (51), A₂₁ andA₂₂ each independently represents a substituted or unsubstitutedaromatic ring group having 6 to 60 carbon atoms. R₂₁ to R₂₈ eachindependently represents a hydrogen atom, a substituted or unsubstitutedaromatic ring group having 6 to 50 carbon atoms, a substituted orunsubstituted aromatic heterocyclic group having 5 to 50 atoms, asubstituted or unsubstituted alkyl group having 1 to 50 carbon atoms, asubstituted or unsubstituted cycloalkyl group, a substituted orunsubstituted alkoxy group having 1 to 50 carbon atoms, a substituted orunsubstituted aralkyl group having 6 to 50 carbon atoms, a substitutedor unsubstituted aryloxy group having 5 to 50 atoms, a substituted orunsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, a silylgroup which is substituted by an alkyl group or an aryl group; or afluorine atom. In particular, the following case is preferable: R₂₁represents a hydrogen atom; R₂₂ represents a hydrogen atom, a phenylgroup, a naphthyl group, a fluorenyl group, a dibenzofuranyl group orthose combination; R₂₃ to R₂₈ each independently represents a hydrogenatom; Ar₂₁ and Ar₂₂ each independently represents a phenyl group, anaphthyl group, a fluorenyl group, a dibenzofuranyl group or thosecombination.

In the pyrene derivative represented by the formula (52), R₃₀ to R₃₉each independently represents a hydrogen atom, a substituted orunsubstituted aromatic ring group having 6 to 50 carbon atoms, asubstituted or unsubstituted aromatic heterocyclic group having 5 to 50atoms, a substituted or unsubstituted alkyl group having 1 to 50 carbonatoms, a substituted or unsubstituted cycloalkyl group, a substituted orunsubstituted alkoxy group having 1 to 50 carbon atoms, a substituted orunsubstituted aralkyl group having 6 to 50 carbon atoms, a substitutedor unsubstituted aryloxy group having 5 to 50 atoms, a substituted orunsubstituted arylthio group having 5 to 50 atoms, a substituted orunsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, a silylgroup which is substituted by an alkyl group or an aryl group; or afluorine atom. In particular, it is preferable that the substituent inR₃₀ to R₃₈ is a phenyl group, a naphthyl group, a fluorenyl group, adibenzofuranyl group or those combinations.

In the anthracene derivative represented by the formula (53), R₄₀ to R₄₉each independently represents a hydrogen atom, an alkyl group, acycloalkyl group, an aryl group which may be substituted, an alkoxylgroup, an aryloxy group, an alkenyl group or a heterocyclic group whichmay be substituted; “I” and “j” each independently represents an integerof 1 to 5, and when “I” or “j” represents 2 or more, R₄₀'s or R₄₁'s maybe identical to or different from each other. Further, R₄₀'s or R₄₁'smay be bonded to each other to form a ring; and any one couple of R₄₂and R₄₃, R₄₄ and R₄₅, R₄₆ and R₄₇, or R₄₈ and R₄₉ may be bonded to eachother to form a ring.

L₁ represents a single bond, O, S, N(R)— (wherein R represents an alkylgroup or an aryl group which may be substituted), an alkylene group oran arylene group.

In the anthracene derivative represented by the formula (54), R₅₀ to R₅₉each independently represents a hydrogen atom, an alkyl group, acycloalkyl group, an aryl group which may be substituted, an alkoxylgroup, an aryloxy group, or a heterocyclic group which may besubstituted; “k”, “1”, “m” and “n” each independently represents aninteger of 1 to 5, and when any one of “k”, “1”, “m” and “n” represents2 or more, R₅₀'s, R₅₁'s, R₅₅'s or R₅₆'s may be identical to or differentfrom each other. Further, R₅₂'s, R₅₃'s, R₅₄'s or R₅₅'s may be bonded toeach other to form a ring; and any one couple of R₅₂ and R₅₃, or R₅₇ andR₅₈ may be bonded to each other to form a ring.

L₂ represents a single bond, O, S, N(R)— (wherein R represents an alkylgroup or an aryl group which may be substituted), an alkylene group oran arylene group.

In the spirofluorene derivative represented by the formula (55), Ar₃₁ toAr₃₄ each independently represents a substituted or unsubstitutedbiphenylyl group or a substituted or unsubstituted naphthyl group.

In the compound represented by the formula (56), Ar₄₁ to Ar₄₃ eachindependently represents a substituted or unsubstituted arylene grouphaving 6 to 60 carbon atoms, and Ar₄₄ to Ar₄₆ each independentlyrepresents a hydrogen atom, or substituted or unsubstituted aryl grouphaving 6 to 60 carbon atoms.

R₆₁ to R₆₃ each independently represents a hydrogen atom, an alkyl grouphaving 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbonatoms, an alkoxyl group having 1 to 6 carbon atoms, an aryloxy grouphaving 5 to 18 carbon atoms, an aralkyloxy group having 7 to 18 carbonatoms, an ester group having 1 to 6 carbon atoms, or a fluorine atom.

In the fluorene compound represented by the formula (57), R₇₃ and R₇₄each independently represents a hydrogen atom, a substituted orunsubstituted alkyl group, a substituted or unsubstituted aralkyl group,a substituted or unsubstituted aryl group, a substituted orunsubstituted heterocyclic group, or a fluorine atom.

R₇₁'s and R₇₂'s bonded to respective fluorene groups may be identical toor different from each other, and R₇₁ and R₇₂ bonded to the samefluorene group may be identical to or different from each other.

R₇₃ and R₇₄ each independently represents a hydrogen atom, a substitutedor unsubstituted alkyl group, a substituted or unsubstituted aralkylgroup, a substituted or unsubstituted aryl group, or a substituted orunsubstituted heterocyclic group. R₇₃'s and R₇₄'s bonded to respectivefluorene groups may be identical to or different from each other, andR₇₃ and R₇₄ bonded to the same fluorene group may be identical to ordifferent from each other.

Ar₇₁ and Ar₇₂ each represents a substituted or unsubstituted fusedpolycyclic aromatic group having three or more benzene rings in total,or a substituted or unsubstituted fused polycyclic heterocyclic groupthat has three or more rings each of which is a benzene ring or aheterocyclic ring in total and that is bonded to a fluorene group bycarbon. Ar₇₁ and Ar₇₂ may be identical to or different from each other;and “v” represents an integer of 1 to 10.

In the pentacene compound represented by the formula (xii), Q¹ to Q¹²each independently represents a hydrogen atom, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms, a substituted orunsubstituted aryl group having 5 to 20 ring carbon atoms, an aminogroup, a substituted or unsubstituted alkoxy group having 1 to 20 carbonatoms, a substituted or unsubstituted alkylthio group having 1 to 20carbon atoms, a substituted or unsubstituted aryloxy group having 5 to20 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 5 to 20 ring carbon atoms, a substituted or unsubstituted alkenylgroup having 2 to 20 carbon atoms, a substituted or unsubstitutedaralkyl group having 7 to 20 ring carbon atoms, or a substituted orunsubstituted heterocyclic group having 5 to 20 ring carbon atoms; whichmay be identical to or different from each other.

The naphthacene derivative represented by the above formula (xii) ismore preferably the naphthacene derivative represented by the followingformula (xiii).

In the formula (xiii), Q³ to Q¹², Q¹⁰¹ to Q¹⁰⁵, and Q²⁰¹ to Q²⁰⁵ eachindependently represents the same group as Q³ to Q¹² in the aboveformula (xii), which may be identical to or different from each other,and adjacent 2 or more Qs among them may be bonded to each other to forma ring.

Among the above materials, the anthracene derivative (the monoanthracenederivative and the asymmetric anthracene is more preferable) and thepentacene derivative are preferable.

Regarding with the material which is suitable for phosphorescent lightemission, a compound having a carbazole ring is preferably used. Thecompound has a function of causing a phosphorescent compound to emitlight as a result of the occurrence of energy transfer from the excitedstate of the compound to the phosphorescent compound. The compound isnot particularly limited as long as it is a compound capable oftransferring exciton energy to a phosphorescent compound, and can beappropriately selected in accordance with a purpose. The compound mayhave, for example, an arbitrary heterocyclic ring in addition to acarbazole ring.

Specific examples of such the compound include carbazole derivatives,triazole derivatives, oxazole derivatives, oxadiazole derivatives,imidazole derivatives, polyarylalkane derivatives, pyrazolinederivatives, pyrazolone derivatives, phenylene diamine derivatives,arylamine derivatives, amino-substituted chalcone derivatives,styrylanthracene derivatives, fluorenone derivatives, hydrazonederivatives, stilbene derivatives, silazane derivatives, aromatictertiary amine compounds, styrylamine compounds, aromaticdimethylidene-based compounds, porphyrin-based compounds,anthraquinodimethane derivatives, anthrone derivatives, diphenylquinonederivatives, thiopyranedioxide derivatives, carbodiimide derivatives,fluorenilidene methane derivatives, distyryl pyrazine derivatives,heterocyclic tetracarboxylic anhydrides such as naphthaleneperylene,phthalocyanine derivatives, various metal complex polysilane-basedcompounds typified by a metal complex of an 8-quinolinol derivative or ametal complex having metal phthalocyanine, benzooxazole, orbenzothiazole as a ligand, poly(N-vinylcarbazole) derivatives,aniline-based copolymers, electrically conductive high molecular weightoligomers such as a thiophene oligomer and polythiophene, polymercompounds such as polythiophene derivatives, polyphenylene derivatives,polyphenylene vinylene derivatives, and polyfluorene derivatives. One ofthe host compounds may be used alone, or two or more of them may be usedin combination. Specific examples thereof include the compounds asdescribed below.

When the aromatic amine derivative of the present invention is used forthe light emitting layer of the organic EL device, the followingmaterials can be used as doping materials.

Examples of the doping materials to be used in the present inventioninclude arylamine compounds, styryl amine compounds, anthracenederivatives, naphthalene derivatives, phenanthrene derivatives, pyrenederivatives, tetracene derivatives, coronene derivatives, chrysenederivatives, benzfluorescein derivatives, perylene derivatives,phthaloperylene derivatives, naphthaloperylene derivatives, perinonederivatives, phthaloperinone derivatives, naphthaloperinone derivatives,diphenyl butadiene derivatives, tetraphenyl butadiene derivatives,coumarin derivatives, oxadiazole derivatives, aldazine derivatives,bisbenzoxazoline derivatives, bis styryl derivatives, pyrazinederivatives, cyclopentadiene derivatives, quinoline metal complexderivatives, aminoquinoline metal complex derivatives, benzoquinolinemetal complex derivatives, imine derivatives, diphenylethylenederivatives, vinyl anthracene derivatives, diamino carbazolederivatives, pyran derivatives, thiopyran derivatives, polymethinederivatives, merocyanine derivatives, imidazole chelated oxynoidderivatives, quinacridone derivatives, rubrene derivatives andfluorescent dye; like already described materials or other materials,though not limited thereto.

In the organic EL device of the present invention, the styrylaminecompounds and/or arylamine compounds are preferably represented by thefollowing general formula (50):

In the general formula (50), Ar₂₇ represents a substituted orunsubstituted monovalent or divalent aromatic group having the number ofcarbon atoms of 6 to 40 forming the aromatic ring, and Ar₂₈ to Ar₂₉ eachindependently represents a substituted or unsubstituted aromatic grouphaving the number of carbon atoms of 6 to 40 forming the aromatic ring;“u” represents an integer of 1 to 4, and especially, “u” preferablyrepresents an integer of 1 or 2. Any one of Ar₂₇ to Ar₂₉ may be anaromatic group having a styryl group. When the general formula (50) is astyryl amine compound, it is preferable that any one of the aromaticgroups Ar₂₇ to Ar₂₉ has the styryl group, or alternatively, that atleast one of Ar₂₈ and Ar₂₉ is preferably substituted by the styrylgroup.

Examples of the aromatic group having the number of carbon atoms of 6 to40 forming the aromatic ring include a phenyl group, a naphthyl group,an anthranyl group, a phenanthryl group, a pyrenyl group, a coronylgroup, a biphenyl group, a terphenyl group, a pyrrolyl group, a furanylgroup, a thiophenyl group, a benzthiophenyl group, an oxadiazolyl group,a diphenylanthranyl group, an indolyl group, a carbazolyl group, apyridyl group, a benzquinolyl group, a fluoranthenyl group, anacenaphthofluoranthenyl group, a stilbene group, a perilenyl group, acrycenyl group, a picenyl group, a triphenylenyl group, a rubicenylgroup, a benzanthracenyl group, a phenylanthranyl group, abisanthracenyl group, or an arylene group represented by the followinggeneral formula (C) or (D). Among those, the naphthyl group, theanthranyl group, the crycenyl group, the pyrenyl group or the arylenegroup represented by the general formula (D) is preferable.

In the formula (C), “r” represents an integer of 1 to 3.

Examples of the polyvalent aromatic group having the number of carbonatoms of 6 to 40 forming the aromatic ring include those prepared byreplacing the above examples of the monovalent aromatic group having 6to 40 ring forming carbon atoms with a polyvalent aromatic group having2 or more valence.

Additionally, the aromatic group having the number of carbon atoms of 6to 40 forming the aromatic ring may be substituted. Preferable examplesof the substituent include an alkyl group having 1 to 6 carbon atoms (anethyl group, a methyl group, an i-propyl group, a n-propyl group, asec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, acyclopentyl group, a cyclohexyl group, etc.); an alkoxy group having 1to 6 carbon atoms (an ethoxy group, a methoxy group, an i-propoxy group,an n-propoxy group, an s-butoxy group, a t-butoxy group, a pentoxygroup, a hexyloxy group, a cyclopentoxy group, a cyclohexyloxy group,etc.); an aryl group having 5 to 40 carbon atoms; an ester group whichhas an aryl group having 5 to 40 carbon atoms; an ester group which hasan alkyl group having 1 to 6 carbon atoms; a fluorine atom, atrialkylsilyl group, a triarylsilyl group, etc.

A phosphorescent dopant is a compound capable of emitting light from atriplet exciton. The phosphorescent dopant is not restricted as long aslight from the triplet exciton is emitted, and is preferably a metalcomplex containing at least one metal selected from the group consistingof Ir, Ru, Pd, Pt, Os and Re, more preferably a porphyrin metal complexor an ortho-metallated metal complex. A porphyrin platinum complex ispreferable as the porphyrin metal complex. One kind of a phosphorescentcompound may be used alone, or two or more kinds of phosphorescentcompounds may be used in combination.

There are various ligands to form the ortho-metallated metal complex,and preferred are 2-phenylpyridine derivatives, 7,8-benzoquinolinederivatives, 2-(2-thienyl)pyridine derivatives, 2-(1-naphthyl)pyridinederivatives, and 2-phenylquinoline derivatives. The derivatives may havea substituent as occasion demands. A fluoride of any one of thosederivatives, or one obtained by introducing a trifluoromethyl group intoany one of those derivatives is a particularly preferable blue-baseddopant. The metal complex may further include a ligand other than theabove-mentioned ligands such as acetylacetonato or picric acid as anauxiliary ligand.

The content of the phosphorescent dopant in the light emitting layer maybe appropriately selected without particular limitation and, forexample, it may be from 0.1 to 70% by mass, preferably from 1 to 30% bymass. When the content of the phosphorescent compound is less than 0.1%by mass, the intensity of emitted light is weak, and an effect of theincorporation of the compound is not sufficiently exerted. When thecontent exceeds 70% by mass, a phenomenon referred to as concentrationquenching becomes remarkable, and device performance reduces.

Subsequently, the electron injecting and transporting layer is a layerwhich helps injection of electrons into the light emitting layer,transports the holes to the light emitting region, and exhibits a greatmobility of electrons. The adhesion improving layer is an electroninjecting layer including a material exhibiting particularly improvedadhesion with the cathode.

In addition, it is known that, in an organic EL device, emitted light isreflected by an electrode (cathode in this case), so emitted lightdirectly extracted from an anode and emitted light extracted via thereflection by the electrode interfere with each other. The thickness ofan electron transporting layer is appropriately selected from the rangeof several nanometers to several micrometers in order that theinterference effect may be effectively utilized. When the thickness isparticularly large, an electron mobility is preferably at least 10⁻⁵cm²/Vs or more upon application of an electric field of 10⁴ to 10⁶ V/cmin order to avoid an increase in voltage.

A metal complex of 8-hydroxyquinoline or of a derivative of8-hydroxyquinoline, or an oxadiazole derivative is suitable as amaterial to be used in the electron injecting layer. Specific examplesof the metal complex of 8-hydroxyquinoline or of the derivative of8-hydroxyquinoline that can be used as an electron injecting materialinclude metal chelate oxynoid compounds each containing a chelate ofoxine (generally 8-quinolinol or 8-hydroxyquinoline), such astris(8-quinolinol)aluminum.

On the other hand, examples of the oxadiazole derivatives includeelectron transfer compounds represented by the following generalformulae:

wherein Ar₈₁, Ar₈₂, Ar₈₃, Ar₈₅, Ar₈₆ and Ar₈₉ each represent asubstituted or unsubstituted aryl group and may represent the same groupor different groups; and Ar₈₄, Ar₈₇ and Ar₈₅ each represent asubstituted or unsubstituted arylene group and may represent the samegroup or different groups.

Examples of the aryl group include a phenyl group, a biphenyl group, ananthryl group, a perilenyl group and a pyrenyl group. Examples of thearylene group include a phenylene group, a naphthylene group, abiphenylene group, an anthranylene group, a perilenylene group, apyrenylene group, etc. Examples of the substituent include an alkylgroup having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbonatoms and a cyano group. As the electron transfer compound, compoundswhich can form thin films are preferable.

Examples of the electron transfer compounds described above include thefollowing.

Further, nitrogen-containing heterocyclic ring derivatives representedby the following general formula are preferably used in the electroninjecting layer and the electron transporting layer (particularly in theelectron transporting layer). As compared with other electrontransporting materials (e.g., Alq), the following nitrogen-containingheterocyclic ring derivatives can enhance the effects of elevating theefficiencies and reducing the driving voltages by using together withthe aromatic amine derivatives of the present invention.

wherein A³³¹ to A³³³ each independently represents a nitrogen atom or acarbon atom; R³³¹ and R³³² each independently represents a substitutedor unsubstituted aryl group having 6 to 60 ring atoms, a substituted orunsubstituted heteroaryl group having 3 to 60 ring atoms, an alkyl grouphaving 1 to 20 carbon atoms, a haloalkyl group having 1 to 20 carbonatoms, or an alkoxy group having 1 to 20 carbon atoms; “n” represents aninteger of 0 to 5, and when “n” is an integer of 2 or more, a pluralityof R³³¹'s may be identical to or different from each other. Further, theplurality of R³³¹ groups adjacent to each other may be bonded to eachother to form a substituted or unsubstituted carbocyclic aliphatic ringor a substituted or unsubstituted carbocyclic aromatic ring.

Ar³³¹ represents a substituted or unsubstituted aryl group having 6 to60 ring atoms or a substituted or unsubstituted heteroaryl group having3 to 60 ring atoms.

Ar³³¹′ represents a substituted or unsubstituted arylene group having 6to 60 ring atoms or a substituted or unsubstituted heteroarylene grouphaving 3 to 60 ring atoms.

Ar³³² represents a hydrogen atom, an alkyl group having 1 to 20 carbonatoms, a haloalkyl group having 1 to 20 carbon atoms, an alkoxy grouphaving 1 to 20 carbon atoms, a substituted or unsubstituted aryl grouphaving 6 to 60 ring atoms, or a substituted or unsubstituted heteroarylgroup having 3 to 60 ring atoms.

However, at least one of Ar³³¹ and Ar³³² represents a substituted orunsubstituted fused ring group having 10 to 60 ring atoms, or asubstituted or unsubstituted hetero fused ring group having 3 to 60 ringatoms.

L³³¹, L³³² and L³³³ each independently represents a single bond, asubstituted or unsubstituted arylene group having 6 to 60 ring atoms, asubstituted or unsubstituted divalent hetero fused ring group having 3to 60 ring atoms or a substituted or unsubstituted fluorenylene group.

The compound represented by the following formula can be used as acompound to be used as other electron transporting materials.

HAr-L-Ar^(1a)—Ar^(2a)(C)

wherein HAr represents a nitrogen-containing heterocyclic ring which has3 to 40 carbon atoms and may have a substituent; “L” represents a singlebond, an arylene group which has 6 to 60 carbon atoms and may have asubstituent, a heteroarylene group which has 3 to 60 carbon atoms andmay have a substituent, or a fluorenylene group which may have asubstituent; Ar^(1a) represents a divalent aromatic hydrocarbon groupwhich has 6 to 60 carbon atoms and may have a substituent; and Ar^(2a)represents an aryl group which has 6 to 60 carbon atoms and may have asubstituent, or a heteroaryl group which has 3 to 60 carbon atoms andmay have a substituent.

wherein Q₁ and Q2 each independently represents a ligand represented bythe following general formula (G), and L represents a halogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedcycloalkyl group, a substituted or unsubstituted aryl group, asubstituted or unsubstituted heterocyclic group, —OR′ (R′ represents ahydrogen atom, a substituted or unsubstituted alkyl group, a substitutedor unsubstituted cycloalkyl group, a substituted or unsubstituted arylgroup, a substituted or unsubstituted heterocyclic group), or a ligandrepresented by —O—Ga-Q³(Q⁴) wherein Q³ and Q⁴ are identical to Q₁ andQ₂.

wherein rings A¹ and A² are six-membered aryl ring structures which arefused with each other and each of which may be substituted.

This metal complex behaves strongly as an n-type semiconductor, and hasa large electron injecting ability. Further, generation energy uponformation of the complex is low. As a result, the metal and the ligandof the formed metal complex are bonded to each other so strongly thatthe fluorescent quantum efficiency of the complex as a light emittingmaterial improves.

Specific examples of a substituent in the rings A¹ and A² which eachform a ligand of the general formula (G) include: a halogen atom such aschlorine, bromine, iodine, or fluorine; a substituted or unsubstitutedalkyl group such as a methyl group, an ethyl group, a propyl group, abutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, ahexyl group, a heptyl group, an octyl group, a stearyl group, ortrichloromethyl group; a substituted or unsubstituted aryl group such asa phenyl group, a naphthyl group, 3-methylphenyl group, 3-methoxyphenylgroup, 3-fluorophenyl group, 3-trichloromethylphenyl group,3-trifluoromethylphenyl group, or a 3-nitrophenyl group; a substitutedor unsubstituted alkoxy group such as a methoxy group, an n-butoxygroup, a t-butoxy group, a trichloromethoxy group, a trifluoroethoxygroup, a pentafluoropropoxy group, 2,2,3,3-tetrafluoropropoxy group,1,1,1,3,3,3-hexafluoro-2-propoxy group, or 6-(perfluoroethyl)hexyloxygroup; a substituted or unsubstituted aryloxy group such as a phenoxygroup, a p-nitrophenoxy group, a p-tert-butylphenoxy group, a3-fluorophenoxy group, a pentafluorophenyl group, or a3-trifluoromethylphenoxy group; a substituted or unsubstituted alkylthiogroup such as a methylthio group, an ethylthio group, a tert-butylthiogroup, a hexylthio group, an octylthio group, or a trifluoromethylthiogroup; a substituted or unsubstituted arylthio group such as aphenylthio group, a p-nitrophenylthio group, a p-tert-butylphenylthiogroup, 3-fluorophenylthio group, a pentafluorophenylthio group, or3-trifluoromethylphenylthio group; a mono-substituted or di-substitutedamino group such as a cyano group, a nitro group, an amino group, amethylamino group, a diethylamino group, an ethylamino group, adiethylamino group, a dipropylamino group, a dibutylamino group, or adiphenylamino group; an acylamino group such as abis(acetoxymethyl)amino group, a bis(acetoxyethyl)amino group, abis(acetoxypropyl)amino group, or a bis(acetoxybutyl)amino group; acarbamoyl group such as a hydroxyl group, a siloxy group, an acyl group,a methylcarbamoyl group, a dimethylcarbamoyl group, an ethylcarbamoylgroup, a diethylcarbamoyl group, a propylcarbamoyl group, abutylcarbamoyl group, or a phenylcarbamoyl group; a cycloalkyl groupsuch as a carboxylic acid group, a sulfonic acid group, an imide group,a cyclopentane group, or a cyclohexyl group; an aryl group such as aphenyl group, a naphthyl group, a biphenylyl group, an anthryl group, aphenanthryl group, a fluorenyl group, or a pyrenyl group; and aheterocyclic group such as a pyridinyl group, a pyrazinyl group, apyrimidinyl group, a pyridazinyl group, a triazinyl group, an indolinylgroup, a quinolinyl group, an acridinyl group, a pyrrolidinyl group, adioxanyl group, a piperidinyl group, a morpholidinyl group, apiperazinyl group, a triathinyl group, a carbazolyl group, a furanylgroup, a thiophenyl group, an oxazolyl group, an oxadiazolyl group, abenzoxazolyl group, a thiazolyl group, a thiadiazolyl group, abenzothiazolyl group, a triazolyl group, an imidazolyl group, abenzoimidazolyl group, or a puranyl group. In addition, theabove-mentioned substituents may be bound to each other to further forma six-membered aryl ring or a heterocycle.

Besides, the nitrogen-containing heterocyclic ring derivativerepresented by the following formula can be also used.

wherein R_(121a) to R_(126a) each independently represents any one of asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedaryl group, a substituted or unsubstituted aralkyl group or asubstituted or unsubstituted heterocyclic ring group. However, R_(121a)to R_(126a) may be identical to or different from each other. Further,R_(121a) and R_(122a), R_(123a) and R_(124a), R_(121a) and R_(126a),R_(121a) and R_(126a), R_(122a) and R_(123a), R_(124a) and R_(125a) mayform a fused ring.

Further, compounds represented by the formula below may be employable.

wherein R₁₃₁ to R₁₃₆ are substituents, and preferably, they eachindependently represents an electron withdrawing group such as a cyanogroup, a nitro group, a sulfonyl group, a carbonyl group, atrifluoromethyl group, a halogen atom, etc.

Typically exemplified as those materials, a material having an acceptorproperty is also employable as a hole injecting material. Specificexamples of those are the same as described hereinabove.

In addition to the above-mentioned aromatic dimethylidene compounddescribed hereinabove as a material for the light emitting layer,inorganic compound such as p-type Si and p-type SiC may be used as thematerial for the hole injecting layer and the hole transporting layer.

A preferable embodiment for the organic EL device of the presentinvention includes an element containing a reducing dopant in the regionof an electron transport or in the interfacial region of the cathode andthe organic layer. The reducing dopant is defined as a substance whichcan reduce a compound having the electron transporting property. Varioussubstances can be used as the reducing dopant as long as the substanceshave a uniform reductive property. For example, at least one substanceselected from the group consisting of alkali metals, alkaline earthmetals, rare earth metals, alkali metal oxides, alkali metal halides,alkaline earth metal oxides, alkaline earth metal halides, rare earthmetal oxides, rare earth metal halides, organic complexes of alkalimetals, organic complexes of alkaline earth metals, and organiccomplexes of rare earth metals can be preferably used.

Examples of the preferable reductive dopant include at least one alkalimetal selected from a group consisting of Li (the work function: 2.9eV), Na (the work function: 2.36 eV), K (the work function: 2.28 eV), Rb(the work function: 2.16 eV) and Cs (the work function: 1.95 eV) or atleast one alkaline earth metals selected from a group consisting of Ca(the work function: 2.9 eV), Sr (the work function: 2.0 to 2.5 eV) andBa (the work function: 2.52 eV). Reductive dopants having a workfunction of 2.9 eV or smaller are particularly preferable. Among those,more preferable reductive dopants include at least one alkali metalselected from the group consisting of K, Rb and Cs, more preferably Rbor Cs and most preferably Cs. Since those alkali metals have aparticularly high reducing capability, the luminance is improved and thelifetime is prolonged by the addition thereof into an electron injectionregion in a relatively small amount. A combination of two or more alkalimetals is also preferably used as the reductive dopant having a workfunction of 2.9 eV or smaller. A combination containing Cs such as Csand Na, Cs and K, Cs and Rb and Cs, Na and K is particularly preferred.By containing Cs in combination, the reducing capability is effectivelyperformed, and the luminance is enhanced and the lifetime is prolongedin the organic EL device by the addition into the electron injectionregion.

The present invention may further include an electron injecting layerwhich is composed of an insulating material or a semiconductor anddisposed between the cathode and the organic layer. At this time, theelectron injecting property can be improved by preventing a leak ofelectric current effectively. As the insulating material, at least onemetal compound selected from the group consisting of alkali metalchalcogenides, alkaline earth metal chalcogenides, alkali metal halides,and alkaline earth metal halides is preferable. It is preferable thatthe electron injecting layer be composed of the above-mentionedsubstance such as the alkali metal chalcogenide since the electroninjecting property can be further improved. To be specific, preferableexamples of the alkali metal chalcogenide include Li₂O, K₂O, Na₂S,Na₂Se, and Na₂O. Preferable examples of the alkaline earth metalchalcogenide include CaO, BaO, SrO, BeO, BaS, and CaSe. Preferableexamples of the alkali metal halide include LiF, NaF, KF, LiCl, KCl, andNaCl. Preferable examples of the alkaline earth metal halide includefluorides such as CaF₂, BaF₂, SrF₂, MgF₂, and BeF₂ and halides otherthan the fluorides.

Examples of the semiconductor constituting the electron transportinglayer include oxides, nitrides and oxide nitrides containing at leastone element selected from Ba, Ca, Sr, Yb, Al, Ga, In, Li, Na, Cd, Mg,Si, Ta, Sb and Zn, which are used singly or in combination of two ormore. It is preferable that the inorganic compound for constituting theelectron transporting layer is in the form of a crystallite or amorphousinsulating thin film. When the electron transporting layer isconstituted with the above insulating thin film, a more uniform thinfilm can be formed and defective pixels such as dark spots can bedecreased. Examples of the inorganic compound include the alkali metalchalcogenides, the alkaline earth metal chalcogenides, the alkali metalhalides and the alkaline earth metal halides which are described above.

The hole injecting and transporting layer is a layer which helps theinjection of holes into the light emitting layer and transports theholes to the light emitting region. The layer exhibits a great mobilityof holes and, in general, has an ionization energy as small as 5.6 eV orsmaller. For the hole injecting and transporting layer, a material whichtransports holes to the light emitting layer at a small strength of theelectric field is preferable. A material which exhibits, for example, amobility of holes of at least 10⁻⁴ cm²/V·s under an electric field offrom 10⁴ to 10⁶ V/cm is preferable.

When the aromatic amine derivative of the present invention is employedin the hole transporting region, the hole injecting and transportinglayer may be composed of the aromatic amine derivative of the presentinvention alone or in combination with another material.

With regard to the material which may be employed for forming the holeinjecting and transporting layer in combination with the aromatic aminederivative of the present invention, any material having the foregoingpreferable properties is employed without particularly restricted, whichis selected from compounds commonly used as a hole transporting materialof photoconductive materials and compounds used for forming the holeinjecting and transporting layer of EL devices. In the presentinvention, a material capable of transporting holes and being employablein a transporting region is defined as a hole transporting material.

Regarding with the aromatic amine derivative to be used for the holeinjecting and transporting layer, compounds represented by the followinggeneral formulae are employable.

wherein Ar²¹¹ to Ar²¹³, Ar²²¹ to Ar²²³ and Ar²⁰³ to Ar²⁰⁸ eachindependently represents a substituted or unsubstituted aromatichydrocarbon group having 6 to 50 ring carbon atoms, a substituted orunsubstituted aromatic heterocyclic group having 5 to 50 ring atoms; a,b, c, p, q and r each independently represents an integer of 0 to 3;Ar²⁰³ and Ar²⁰⁴, Ar²⁰⁵ and Ar²⁰⁶, Ar²⁰⁷ and Ar²⁰⁸ may be bonded to eachother to form a saturated or unsaturated ring.

Examples of the substituted or unsubstituted aromatic hydrocarbon grouphaving 6 to 50 ring carbon atoms include a phenyl group, 1-naphthylgroup, 2-naphthyl group, 1-anthryl group, 2-anthryl group, 9-anthrylgroup, 1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group,4-phenanthryl group, 9-phenanthryl group, 1-naphthacenyl group,2-naphthacenyl group, 9-naphthacenyl group, 1-pyrenyl group, 2-pyrenylgroup, 4-pyrenyl group, 2-biphenylyl group, 3-biphenylyl group,4-biphenylyl group, p-terphenyl-4-yl group, p-terphenyl-3-yl group,p-terphenyl-2-yl group, m-terphenyl-4-yl group, m-terphenyl-3-yl group,m-terphenyl-2-yl group, o-tolyl group, m-tolyl group, p-tolyl group,p-tert-butylphenyl group, p-(2-phenylpropyl)phenyl group,3-methyl-2-naphthyl group, 4-methyl-1-naphthyl group, 4-methyl-1-anthrylgroup, 4′-methylbiphenyl-yl group, 4″-tert-butyl-p-terphenyl-4-yl group.

Specific examples of the substituted or unsubstituted aromaticheterocyclic group having 5 to 50 ring atoms include 1-pyrrolyl group,2-pyrrolyl group, 3-pyrrolyl group, pyradinyl group, 2-pyridinyl group,3-pyridinyl group, 4-pyridinyl group, 1-indolyl group, 2-indolyl group,3-indolyl group, 4-indolyl group, 5-indolyl group, 6-indolyl group,7-indolyl group, 1-isoindolyl group, 2-isoindolyl group, 3-isoindolylgroup, 4-isoindolyl group, 5-isoindolyl group, 6-isoindolyl group,7-isoindolyl group, 2-furyl group, 3-furyl group, 2-benzofuranyl group,3-benzofuranyl group, 4-benzofuranyl group, 5-benzofuranyl group,6-benzofuranyl group, 7-benzofuranyl group, 1-isobenzofuranyl group,3-isobenzofuranyl group, 4-isobenzofuranyl group, 5-isobenzofuranylgroup, 6-isobenzofuranyl group, 7-isobenzofuranyl group, quinolyl group,3-quinolyl group, 4-quinolyl group, 5-quinolyl group, 6-quinolyl group,7-quinolyl group, 8-quinolyl group, 1-isoquinolyl group, 3-isoquinolylgroup, 4-isoquinolyl group, 5-isoquinolyl group, 6-isoquinolyl group,7-isoquinolyl group, 8-isoquinolyl group, 2-quinoxanyl group,5-quinoxanyl group, 6-quinoxanyl group, 1-carbazolyl group, 2-carbazolylgroup, 3-carbazolyl group, 4-carbazolyl group, 9-carbazolyl group,1-phenanthridinyl group, 2-phenanthridinyl group, 3-phenanthridinylgroup, 4-phenanthridinyl group, 6-phenanthridinyl group,7-phenanthridinyl group, 8-phenanthridinyl group, 9-phenanthridinylgroup, 10-phenanthridinyl group, 1-acridinyl group, 2-acridinyl group,3-acridinyl group, 4-acridinyl group, 9-acridinyl group,1,7-phenanthrolin-2-yl group, 1,7-phenanthrolin-3-yl group,1,7-phenanthrolin-4-yl group, 1,7-phenanthrolin-5-yl group,1,7-phenanthrolin-6-yl group, 1,7-phenanthrolin-8-yl group,1,7-phenanthrolin-9-yl group, 1,7-phenanthrolin-10-yl group,1,8-phenanthrolin-2-yl group, 1,8-phenanthrolin-3-yl group,1,8-phenanthrolin-4-yl group, 1,8-phenanthrolin-5-yl group,1,8-phenanthrolin-6-yl group, 1,8-phenanthrolin-7-yl group,1,8-phenanthrolin-9-yl group, 1,8-phenanthrolin-10-yl group,1,9-phenanthrolin-2-yl group, 1,9-phenanthrolin-3-yl group,1,9-phenanthrolin-4-yl group, 1,9-phenanthrolin-5-yl group,1,9-phenanthrolin-6-yl group, 1,9-phenanthrolin-7-yl group,1,9-phenanthrolin-8-yl group, 1,9-phenanthrolin-10-yl group,1,10-phenanthrolin-2-yl group, 1,10-phenanthrolin-3-yl group,1,10-phenanthrolin-4-yl group, 1,10-phenanthrolin-5-yl group,2,9-phenanthrolin-1-yl group, 2,9-phenanthrolin-3-yl group,2,9-phenanthrolin-4-yl group, 2,9-phenanthrolin-5-yl group,2,9-phenanthrolin-6-yl group, 2,9-phenanthrolin-7-yl group,2,9-phenanthrolin-8-yl group, 2,9-phenanthrolin-10-yl group,2,8-phenanthrolin-1-yl group, 2,8-phenanthrolin-3-yl group,2,8-phenanthrolin-4-yl group, 2,8-phenanthrolin-5-yl group,2,8-phenanthrolin-6-yl group, 2,8-phenanthrolin-7-yl group,2,8-phenanthrolin-9-yl group, 2,8-phenanthrolin-10-yl group,2,7-phenanthrolin-1-yl group, 2,7-phenanthrolin-3-yl group,2,7-phenanthrolin-4-yl group, 2,7-phenanthrolin-5-yl group,2,7-phenanthrolin-6-yl group, 2,7-phenanthrolin-8-yl group,2,7-phenanthrolin-9-yl group, 2,7-phenanthrolin-10-yl group,1-phenazinyl group, 2-phenazinyl group, 1-phenothiazinyl group,2-phenothiazinyl group, 3-phenothiazinyl group, 4-phenothiazinyl group,10-phenothiazinyl group, 1-phenoxazinyl group, 2-phenoxazinyl group,3-phenoxazinyl group, 4-phenoxazinyl group, 10-phenoxazinyl group,2-oxazolyl group, 4-oxazolyl group, 5-oxazolyl group, 2-oxadiazolylgroup, 5-oxadiazolyl group, 3-furazanyl group, 2-thienyl group,3-thienyl group, 2-methylpyrrol-1-yl group, 2-methylpyrrol-3-yl group,2-methylpyrrol-4-yl group, 2-methylpyrrol-5-yl group,3-methylpyrrol-1-yl group, 3-methylpyrrol-2-yl group,3-methylpyrrol-4-yl group, 3-methylpyrrol-5-yl group,2-tert-butylpyrrol-4-yl group, 3-(2-phenylpropyl)pyrrol-1-yl group,2-methyl-1-indolyl group, 4-methyl-1-indolyl group, 2-methyl-3-indolylgroup, 4-methyl-3-indolyl group, 2-tert-butyl-1-indolyl group,4-tert-butyl-1-indolyl group, 2-tert-butyl-3-indolyl group,4-tert-butyl-3-indolyl group.

Further, the compound represented by the following formula can be usedfor the hole injecting layer and the hole transporting layer.

wherein Ar²³¹ to Ar²³⁴ each independently represents a substituted orunsubstituted aromatic hydrocarbon group having 6 to 50 ring carbonatoms, or a substituted or unsubstituted aromatic heterocyclic grouphaving 5 to 50 ring atoms. L represents a bonding group, which is asingle bond, a substituted or unsubstituted aromatic hydrocarbon grouphaving 6 to 50 ring carbon atoms, or a substituted or unsubstitutedaromatic heterocyclic ring group having 5 to 50 ring atoms; and xrepresents an integer of 0 to 5. Also, Ar²³² and Ar²³³ may be bonded toeach other to form a saturated or unsaturated ring. Specific examples ofthe substituted or unsubstituted aromatic hydrocarbon group having 6 to50 ring carbon atoms and the substituted or unsubstituted aromaticheterocyclic group having 5 to 50 ring atoms include the same as thoseabove mentioned description.

Furthermore, specific examples of the materials for the hole injectinglayer and hole transporting layer include triazole derivatives,oxadiazole derivatives, imidazole derivatives, poly arylalkanederivatives, pyrazoline derivatives and pyrazolone derivatives,phenylenediamine derivatives, arylamine derivatives, amino substitutedchalcone derivatives, oxazole derivatives, styryl anthracenederivatives, fluorenone derivatives, hydrazone derivatives, stilbenederivatives, silazane derivatives, aniline based copolymers,electrically conductive polymer oligomers (in particular, thiopheneoligomers), etc.

Specific examples include triazole derivatives (see, for example, U.S.Pat. No. 3,112,197), oxadiazole derivatives (see, for example, U.S. Pat.No. 3,189,447), imidazole derivatives (see, for example, JP-B 37-16096,etc.), polyarylalkane derivatives (see, for example, U.S. Pat. Nos.3,615,402; 3,820,989; 3,542,544, JP-B 45-555, JP-B 51-10983, JP51-93224A, JP 55-17105A, JP 56-4148A, JP 55-108667A, JP 55-156953A, JP56-36656A, etc.), pyrazoline derivatives and pyrazolone derivatives(see, for example, U.S. Pat. Nos. 3,180,729; 4,278,746; JP 55-88064A, JP55-88065A, JP 49-105537A, JP 55-51086A, JP 56-80051A, JP 56-88141A, JP57-45545A, JP 54-112637A and JP 55-74546A), phenylenediamine derivatives(see, for example, U.S. Pat. No. 3,615,404; JP-B 51-10105, JP-B 46-3712,JP-B 47-25336, JP 54-53435A, JP 54-110536A and JP 54-119925A), arylaminederivatives (see, for example, U.S. Pat. Nos. 3,567,450; 3,180,703;3,240,597; 3,658,520; 4,232,103; 4,175,961; 4,012,376; JP-B 49-35702, JP39-27577B, JP 55-144250A, JP 56-119132A, JP 56-22437A and German PatentNo. 1,110,518), amino-substituted chalcone derivatives (see, forexample, U.S. Pat. No. 3,526,501), oxazole derivatives (disclosed inU.S. Pat. No. 3,257,203, etc.), styrylanthracene derivatives (see, forexample, JP 56-46234A), fluorenone derivatives (see, for example, JP54-110837A), hydrazone derivatives (see, for example, U.S. Pat. No.3,717,462, JP 54-59143A, JP 55-52063A, JP 55-52064A, JP 55-46760A, JP55-85495A, JP 57-11350A, JP 57-148749A and JP 2-311591A), stilbenederivatives (see, for example, JP 61-210363A, JP 61-228451A, JP61-14642A, JP 61-72255A, JP 62-47646A, JP 62-36674A, JP 62-10652A, JP62-30255A, JP 60-93455A, JP 60-94462A, JP 60-174749A, JP 60-175052A,etc.), silazane derivatives (U.S. Pat. No. 4,950,950), polysilane-basedpolymer (JP 2-204996A), aniline based copolymer (JP 2-282263A), etc.

With regard to the material for the hole injecting and transportinglayer, the above materials are also employable, and porphyrin compounds(disclosed in, for example, JP 63-295665 A), aromatic tertiary aminecompounds and styryl amine compounds (see, for example, U.S. Pat. No.4,127,412, JP 53-27033A, JP 54-58445A, JP 55-79450A, JP 55-144250A, JP56-119132A, JP 61-295558A, JP 61-98353A and JP 63-295695A) arepreferable and the aromatic tertiary amine compounds are particularlypreferable.

Further examples include, 4,4′-bis(N-(1-naphthyl)-N-phenylamino)biphenyl(NPD) which has 2 fused aromatic rings in the molecule thereof describedin U.S. Pat. Nos. 5,061,569 and4,4′,4″-tris(N-(3-methylphenyl)-N-phenylamino)triphenylamine (MTDATA)described in JP 4-308688A which includes three triphenylamine unitsconnected in a star burst configuration.

Besides, a nitrogen-containing compound with heterocyclic ringderivative represented by the following general formula disclosed inJapanese Registered Patent No. 03571977 is also employable.

wherein R¹²¹ to R¹²⁶ each independently represents any one of asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedaryl group, a substituted or unsubstituted aralkyl group or asubstituted or unsubstituted heterocyclic group. However, R¹²¹ to R¹²⁶may be the same with or different from each other. Further, R¹²¹ andR¹²², R¹²³ and R¹²⁴, R¹²⁵ and R¹²⁶, R¹²¹ and R¹²⁶, R¹²² and R¹²³, R¹²⁴and R¹²⁵ may form a fused ring.

Still further, a compound represented by the following formula disclosedin US Patent Application Publication No. 2004/0113547 is alsoemployable.

wherein R¹³¹ to R¹³⁶ are substituents, and preferably, they eachindependently represents an electron withdrawing group such as a cyanogroup, a nitro group, a sulfonyl group, a carbonyl group, atrifluoromethyl group, a halogen atom, etc.

Typically exemplified as those materials, a material having an acceptorproperty is also employable as a hole injecting material. Specificexamples of those are the same as described above.

In addition to the above-mentioned aromatic dimethylidene compounddescribed as a material for the light emitting layer, inorganic compoundsuch as p-type Si and p-type SiC may be used as the material for thehole injecting and transporting layer.

To form the hole injecting and transporting layer, a thin film may beformed from the aromatic amine derivative of the present invention inaccordance with a well-known process such as the vacuum vapor depositionprocess, the spin coating process, the casting process and the LBprocess. Although the thickness of the hole injecting and transportinglayer is not particularly limited, the thickness is usually from 5 nm to5 μm. The hole injecting and transporting layer may be a single layermade of one or more kinds of materials mentioned above or may belaminated with another hole injecting and transporting layer made of adifferent material, as long as the hole injecting and transporting layercontains the aromatic amine derivative of the present invention in thehole transporting region thereof.

An organic semiconductor layer which preferably has an electricconductance of 10⁻¹⁰ S/cm or greater may be provided to assist theinjection of holes into the light emitting layer. Examples of thematerials for the organic semiconductor layer include electricallyconductive oligomers such as an oligomer having thiophene and anoligomer having arylamine disclosed in JP 8-193191A; and electricallyconductive dendrimers such as a dendrimer having an arylamine dendrimer.

The materials which are usually used in the organic EL devices can beused for forming the hole injecting layer or the hole transportinglayer. Specific examples of include triazole derivatives, oxadiazolederivatives, imidazole derivatives, poly arylalkane derivatives,pyrazoline derivatives and pyrazolone derivatives, phenylenediaminederivatives, arylamine derivatives, amino substituted chalconederivatives, oxazole derivatives, styryl anthracene derivatives,fluorenone derivatives, hydrazone derivatives, stilbene derivatives,silazane derivatives, polysilane based and aniline based copolymers,electrically conductive polymer oligomers, etc. The materials which areusually used in the organic EL devices can be used for forming theelectron transporting layer. As the material for the electrontransporting layer, 8-hydroxyquinoline, metal complexes of derivativesthereof and oxadiazole derivatives are preferable. Specific examples ofthe metal complex of 8-hydroxyquinoline or of the derivative of8-hydroxyquinoline include metal chelate oxynoid compounds eachcontaining a chelate of oxine (generally 8-quinolinol or8-hydroxyquinoline), such as tris(8-quinolinol)aluminum. Regarding withthe thickness and the method for formation of these layers, thoseusually used for the organic EL device may be appropriately adopted.

The electron injecting material is preferably made of compounds whichhave a good electron transportability as well as excellent capabilitiesof accepting electrons injected from the cathode and injecting theelectrons into the light emitting layer or light emitting material,prevent excited particles produced in the light emitting layer frommoving into the hole injecting layer, and exhibit an excellentcapability of forming a thin film. Specific examples of the compoundinclude fluorenone, anthraquinodimethane, diphenoquinone,thiopyranedioxide, oxazole, oxadiazole, triazole, imidazole,perylenetetracarboxylic acid, fluorenylidenemethane,anthraquinodimethane, anthrone, and derivatives thereof, but thecompound is not limited thereto. Further, an electron acceptingsubstance and an electron donating substance may be added to the holeinjecting material and the electron injecting material, respectively,for enhancing sensitization thereof.

In order to prepare the organic EL device of the present invention, forexample, the anode, the light emitting layer, the hole injecting layerand the electron injecting layer are formed in accordance with theillustrated process using the illustrated materials, and the cathode isformed in the last step. Alternatively, each layer may be formed in areverse order from the cathode to the anode.

Hereinafter, an embodiment of the process for preparing an organic ELdevice having a construction in which the anode, the hole injectinglayer, the light emitting layer, the electron injecting layer, and thecathode are disposed successively on a light transmissive substrate willbe described.

First, on a suitable light transmissive substrate, a thin film of ananode substance is formed so as to have a film thickness of 1 μm orthinner, preferably from 10 nm to 200 nm in accordance with a vapordeposition process, a sputtering process, etc. Then, a hole injectinglayer is formed on the anode. The hole injecting layer can be formed inaccordance with the vacuum vapor deposition process, the spin coatingprocess, the casting process or the LB process, as described above. Thevacuum vapor deposition process is preferable because a uniform film canbe easily obtained and pinhole is little formed. When the hole injectinglayer is formed in accordance with the vacuum vapor deposition process,the conditions are preferably selected from the following ranges:temperature of deposition source: 50 to 450° C.; degree of vacuum: 10⁻⁷to 10⁻³ Ton; vapor deposition rate: 0.01 to 50 nm/s; temperature of thesubstrate: 50 to 300° C.; and film thickness: 5 nm to 5 μm; althoughdepending on the employed compound (material for the hole injectinglayer), the crystal structure and the recombination structure.

Subsequently, the light emitting layer is formed on the hole injectinglayer by depositing a thin film of the organic light emitting materialin accordance with the vacuum vapor deposition process, the sputteringprocess, the spin coating process or the casting process. The vacuumvapor deposition process is preferable because a uniform film can beeasily obtained and pinhole is little formed. When the light emittinglayer is formed in accordance with the vacuum vapor deposition process,the conditions of the vacuum vapor deposition can be selected in thesame ranges as in the deposition of the hole injecting layer, althoughdepending on the compound to be used. With regard to the film thickness,it is preferable to be within the range of from 10 to 40 nm.

Subsequently, the electron injecting layer is formed on the lightemitting layer. Similarly to the formation of the hole injecting layerand light emitting layer, the electron injecting layer is preferablyformed in accordance with the vacuum vapor deposition process, because auniform film is required. The conditions of the vacuum vapor depositioncan be selected from the same ranges as in the formation of the holeinjecting layer and the light emitting layer.

Finally, the cathode is formed on the electron injecting layer, toobtain an organic EL device. The cathode is made of a metal and can beformed in accordance with the vacuum vapor deposition process or thesputtering process. However, the vacuum vapor deposition process ispreferably employed in order to prevent the underlying organic layersfrom being damaged during the formation of the film.

In the above fabrication of the organic EL device, the layers from theanode to the cathode are successively formed preferably in a singleevacuation operation.

The process for forming the layers in the organic EL device of thepresent invention is not particularly limited. A conventional processsuch as the vacuum vapor deposition process and the spin coating processor so can be employed. The organic thin film layer containing thecompound of the formula (1) included in the organic EL device of thepresent invention can be formed in accordance with the vacuum vapordeposition process, the molecular beam epitaxy process (the MBE process)or a known method of coating a solution of the compound such as thedipping process, the spin coating process, the casting process, the barcoating process and the roller coating process. Although the thicknessof each layer in the organic thin film layer in the organic EL device ofthe present invention is not particularly limited, a thickness in therange of several nanometers to 1 μm is preferable usually in order toavoid defects such as pin holes, and to improve the efficiency.

The organic EL device emits light when a direct voltage of 5 to 40 V isapplied with the anode being+terminal and the cathode being−terminal. Inthe reverse polarity, no electric current flows and no light is emittedupon the application of voltage. When an alternating voltage is applied,the uniform light emission is observed only in the polarity where theanode is + and the cathode is −. When an alternating voltage is appliedto the organic EL device, any type of wave shape can be used.

EXAMPLES

This invention will be described in further detail with reference toExamples, which does not limit the scope of this invention.

The structural formulae of Intermediates 1 to 17 and 18 to 27 to beproduced in Synthesis Examples 1 to 17 and 18 to 27 are as shown below.

Synthesis Example 1 Synthesis of Intermediate 1

Under an argon gas flow, 47 g of 4-bromobiphenyl, 23 g of iodine, 9.4 gof periodic acid dihydrate, 42 ml of water, 360 ml of acetic acid and 11ml of sulfuric acid were placed into a 1000-ml three-necked flask. Afterstirring the resultant solution at 65° C. for 30 minutes, the reactionwas allowed to proceed at 90° C. for 6 hours. The resultant mixture waspoured into iced water, and then filtered. After having been washed withwater, the resultant was washed with methanol to obtain 67 g of a whitepowder. The white powder was identified as Intermediate 1 from theanalysis in accordance with Field Desorption Mass Spectrum (hereinafter,FD-MS) because the main peaks of m/z=358 and 360 were shown forC₁₂H₈BrI=359.

Synthesis Example 2 Synthesis of Intermediate 2

Performing a reaction in the same manner as in Synthesis Example 1except that 2-bromo-9,9-dimethylfluorene was used instead of4-bromobiphenyl, 61 g of a white powder was obtained. The white powderwas identified as Intermediate 2 from the analysis in accordance withthe FD-MS because the main peaks of m/z=398 and 400 were shown forC₁₅H₁₂BrI=399.

Synthesis Example 3 Synthesis of Intermediate 3

Providing 150 g (892 mmol) of dibenzofuran and 1 liter of acetic acidinto a flask, the inside of the flask was replaced with the nitrogen gasand the resultant mixture was heated and dissolved. After dropping 188 g(1.18 mol) of bromine while sometimes cooling with water, the mixturewas stirred under air-cooling for 20 hours. The precipitated crystal wasseparated by filtration, washed with acetic acid and water sequentially,and was dried under reduced pressure. After refining the resultantcrystal with reduced-pressure distillation, it was subjected tore-crystallization with methanol repeatedly several times to obtain 66.8g (yield: 31%) of 2-bromodibenzofran.

Under the atmosphere of argon gas, 400 ml of anhydrous THF was added to24.7 g (100 mmol) of 2-bromodibenzofuran, and while stirring at −40° C.,a hexane solution of n-butyllithium with 1.6 M concentration in anamount of 63 ml (100 mmol) was further added. The reacted solution wasstirred for 1 hour while warming up to a temperature of 0° C. Coolingthe reacted solution down to −78° C. again, 50 ml solution of dried THFof trimethyl borate in an amount of 26.0 g (250 mmol) was dropped. Thereacted solution was stirred at a room temperature for 5 hours. Adding100 ml of 1N hydrochloric acid and after stirring the resultant solutionfor 1 hour, a water layer was removed. After drying an organic layerover magnesium sulfate, the solvent was distillated away under a reducedpressure. The resultant solid was washed with toluene to obtain 15.2 g(yield: 72%) of dibenzofuran-2-boronic acid. The resultant wasidentified as Intermediate 3 from the analysis in accordance with theFD-MS because the main peak of m/z=212 was shown for C₁₂H₉BO₃=212.

Synthesis Example 4 Synthesis of Intermediate 4

Into a three-necked flask, 250 g of m-terphenyl (manufactured bySIGMA-ALDRICH Corp.), 50 g of hydroiodic acid-dihydrate, 75 g of iodine,750 ml of acetic acid and 25 ml of sulfuric acid were placed; and theywere allowed to react each other at 70° C. for 3 hours. After thereaction, 5 l of methanol was entered into the resultant, followed bystirring for 1 hour. The mixture was taken by filtration, and theresultant crystal was subjected to column chromatography purification,followed by re-crystallization with acetonitrile to obtain 64 g of awhite powder. The resultant white powder was identified as Intermediate4 from the result in accordance with the FD-MS analysis.

Synthesis Example 5 Synthesis of Intermediate 5

Under the atmosphere of argon gas, 300 ml of toluene and 150 ml of 2 Mconcentration sodium carbonate aqueous solution was added to 28.3 g (100mmol) of 4-iodobromobenzene, 22.3 g (105 mmol) of dibenzofuran-4-boronicacid and 2.31 g (2.00 mmol) of tetrakis(triphenylphosphine)palladium(0), and the resultant mixture solution was heated while refluxing for10 hours.

After the reaction was completed, filtration was carried out immediatelyand a water layer was removed. After drying the organic layer oversodium sulfate, the resultant was concentrated. The residue wassubjected to a chromatography purification using a silica gel column toobtain 26.2 g of 4-(4-bromophenyl)dibenzofuran in the state of a whitecrystal (yield: 81%). The resultant white crystal was identified asIntermediate 5 from the result in accordance with the FD-MS analysis.

Synthesis Example 6 Synthesis of Intermediate 6

Performing a reaction in the same manner as in Synthesis Example 5except that 36 g of Intermediate 1 was used instead of4-iodobromobenzene, 28.1 g of a white powder was obtained. The resultantwhite powder was identified as Intermediate 6 from the result inaccordance with the FD-MS analysis.

Synthesis Example 7 Synthesis of Intermediate 7

Performing a reaction in the same manner as in Synthesis Example 5except that 40 g of Intermediate 2 was used instead of4-iodobromobenzene, 30.2 g of a white powder was obtained. The resultantwhite powder was identified as Intermediate 7 from the result inaccordance with the FD-MS analysis.

Synthesis Example 8 Synthesis of Intermediate 8

Performing a reaction in the same manner as in Synthesis Example 7except that 12.8 g of phenylboronic acid was used instead ofdibenzofuran-4-boronic acid, 19.7 g of a white powder was obtained. Theresultant white powder was identified as Intermediate 8 from the resultin accordance with the FD-MS analysis.

Synthesis Example 9 Synthesis of Intermediate 9

Performing a reaction in the same manner as in Synthesis Example 5except that 22.3 g of Intermediate 3 was used instead ofdibenzofuran-4-boronic acid, 23.1 g of a white powder was obtained. Theresultant white powder was identified as Intermediate 9 from the resultin accordance with the FD-MS analysis.

Synthesis Example 10 Synthesis of Intermediate 10

Performing a reaction in the same manner as in Synthesis Example 6except that 22.3 g of Intermediate 3 was used instead ofdibenzofuran-4-boronic acid, 25.8 g of a white powder was obtained. Theresultant white powder was identified as Intermediate 10 from the resultin accordance with the FD-MS analysis.

Synthesis Example 11 Synthesis of Intermediate 11

Performing a reaction in the same manner as in Synthesis Example 7except that 22.3 g of Intermediate 3 was used instead ofdibenzofuran-4-boronic acid, 27.8 g of a white powder was obtained. Theresultant white powder was identified as Intermediate 11 from the resultin accordance with the FD-MS analysis.

Synthesis Example 12 Synthesis of Intermediate 12

Under an argon gas flow, 5.7 g of benzamide (manufactured by TOKYOChemical Industries, Co., Ltd.), 32.3 g of 4-bromo-p-terphenyl(manufactured by Tokyo Chemical Industries, Co., Ltd.), 1.64 g of copper(I) iodide (manufactured by Wako Pure Chemical Industries, Ltd.), 1.52 gof N,N′-dimethylethylenediamine (manufactured by SIGMA-ALDRCH Corp.),23.2 g of potassium carbonate (manufactured by Wako Pure ChemicalIndustries, Ltd.), and 120 ml of xylene were placed into a 200-mlthree-necked flask, and the reaction was allowed to proceed at 130° C.for 36 hours.

The resultant solution was cooled down, filtered and washed withtoluene. Further, after washing with water and methanol, the solutionwas dried to obtain 23 g of a pale yellow powder.

Into a 300 ml three-necked flask, 23.0 g of the above white powder, 24.8g of potassium hydroxide (manufactured by Wako Pure Chemical Industries,Ltd.), 21 ml of ion-exchange water, 28 ml of xylene (manufactured byWako Pure Chemical Industries, Ltd.) and 15 ml of ethanol (manufacturedby Wako Pure Chemical Industries, Ltd.) were entered, and the resultantmixture solution was heated while being refluxed for 36 hours. After thereaction was completed, extraction with toluene was carried out and theextract was dried over magnesium sulfate. The dried substance wascondensed under reduced pressure and the coarse product was subjected tocolumn purification. The purified substance was re-crystallized with ause of toluene and after the resultant crystal was taken by filtration,the crystal was dried and as a result, 11.2 g of Intermediate Compound12 in the state of a white powder was obtained.

Synthesis Example 13 Synthesis of Intermediate 13

Performing a reaction in the same manner as in Synthesis Example 12except that Intermediate 4 was used instead of 4-bromo-p-terphenyl, 8.2g of a white powder was obtained. The resultant white powder wasidentified as Intermediate 13 from the result in accordance with theFD-MS analysis.

Synthesis Example 14 Synthesis of Intermediate 14

Performing a reaction in the same manner as in Synthesis Example 12except that Intermediate 8 was used instead of 4-bromo-p-terphenyl, 9.1g of a white powder was obtained. The resultant white powder wasidentified as Intermediate 14 from the result in accordance with theFD-MS analysis.

Synthesis Example 15 Synthesis of Intermediate 15

Performing a reaction in the same manner as in Synthesis Example 12except that 16.2 g of 4-bromo-p-terphenyl was used, and 8.8 g of1-acetamide naphthalene was used instead of benzamide, 6.2 g of a whitepowder was obtained. The resultant white powder was identified asIntermediate 15 from the result in accordance with the FD-MS analysis.

Synthesis Example 16 Synthesis of Intermediate 16

Performing a reaction in the same manner as in Synthesis Example 12except that Intermediate 5 was used instead of 4-bromo-p-terphenyl, 7.3g of a white powder was obtained. The resultant white powder wasidentified as Intermediate 16 from the result in accordance with theFD-MS analysis.

Synthesis Example 17 Synthesis of Intermediate 17

Performing a reaction in the same manner as in Synthesis Example 12except that Intermediate 5 was used instead of 4-bromo-p-terphenyl, 8.1g of a white powder was obtained. The resultant white powder wasidentified as Intermediate 17 from the result in accordance with theFD-MS analysis.

Synthesis Example 18 Synthesis of Intermediate 18

Performing a reaction in the same manner as in Synthesis Example 5except that 28.3 g of 3-iodobromobenzene was used instead of4-iodobromobenzene, 21.5 g of a white powder was obtained. The resultantwhite powder was identified as Intermediate 18 from the result inaccordance with the FD-MS analysis.

Synthesis Example 19 Synthesis of Intermediate 19

Performing a reaction in the same manner as in Synthesis Example 3except that 32.3 g of Intermediate 18 was used instead2-bromodibenzofuran; 20.2 g of a white powder was obtained. Theresultant white powder was identified as Intermediate 19 from the resultin accordance with the FD-MS analysis.

Synthesis Example 20 Synthesis of Intermediate 20

Performing a reaction in the same manner as in Synthesis Example 5except that 30.3 g of Intermediate 19 was used instead ofdibenzofuran-4-boronic acid, 31.9 g of a white powder was obtained. Theresultant white powder was identified as Intermediate 20 from the resultin accordance with the FD-MS analysis.

Synthesis Example 21 Synthesis of Intermediate 21

Performing a reaction in the same manner as in Synthesis Example 18except that 22.3 g of Intermediate 3 was used instead ofdibenzofuran-4-boronic acid, 25.9 g of a white powder was obtained. Theresultant white powder was identified as Intermediate 21 from the resultin accordance with the FD-MS analysis.

Synthesis Example 22 Synthesis of Intermediate 22

Performing a reaction in the same manner as in Synthesis Example 3except that 32.3 g of Intermediate 21 was used instead of2-bromodibenzofuran, 21.6 g of a white powder was obtained. Theresultant white powder was identified as Intermediate 22 from the resultin accordance with the FD-MS analysis.

Synthesis Example 23 Synthesis of Intermediate 23

Performing a reaction in the same manner as in Synthesis Example 5except that 30.3 g of Intermediate 22 was used instead ofdibenzofuran-4-boronic acid, 30.6 g of a white powder was obtained. Theresultant white powder was identified as Intermediate 23 from the resultin accordance with the FD-MS analysis.

Synthesis Example 24 Synthesis of Intermediate 24

Performing a reaction in the same manner as in Synthesis Example 12except that Intermediate 18 was used instead of 4-bromo-p-terphenyl, 9.8g of a white powder was obtained. The resultant white powder wasidentified as Intermediate 24 from the result in accordance with theFD-MS analysis.

Synthesis Example 25 Synthesis of Intermediate 25

Performing a reaction in the same manner as in Synthesis Example 12except that Intermediate 21 was used instead of 4-bromo-p-terphenyl,10.2 g of a white powder was obtained. The resultant white powder wasidentified as Intermediate 25 from the result in accordance with theFD-MS analysis.

Synthesis Example 26 Synthesis of Intermediate 26

Under the atmosphere of argon gas, 1000 ml of toluene and 500 ml of 2 Mconcentration sodium carbonate aqueous solution was added to 120.0 g(399 mmol) of 1-bromo-3-fluoro-4-iodobromobenzene, 72.7 g (479 mmol) of2-methoxyphenyl boronic acid and 9.2 g (7.96 mmol) oftetrakis(triphenylphosphine) palladium (0), and the resultant mixturesolution was heated while being refluxed for 10 hours.

After the reaction was completed, extraction with toluene was carriedout immediately and a water layer was removed. After drying the organiclayer over sodium sulfate, the resultant was condensed. The residue wassubjected to a chromatography purification using a silica gel column toobtain 89.6 g of 4-bromo-2-fluoro-2′-methoxybiphenyl in the state ofwhite crystal (yield: 80%).

Under the atmosphere of argon gas, 900 ml of dichloromethane was addedto 89.6 g (319 mmol) of 4-bromo-2-fluoro-2′-methoxybiphenyl, and theresultant mixture solution was stirred while cooling with ice. Afteradding 95.9 g (382 mmol) of boron tribromide by dropping, the solutionwas stirred at a room temperature for 12 hours.

After completion of the reaction, 200 ml of water was added, and theresultant mixture solution was stirred for 1 hour, followed by removinga water layer. After drying the organic layer over magnesium sulfate,the resultant was condensed. The residue was subjected to achromatography purification using a silica gel column to obtain 68.1 gof 4-bromo-2-fluoro-2′-hydroxybiphenyl in the state of white crystal(yield: 70%).

Onto 68.1 g (255 mmol) of 4-bromo-2-fluoro-2′-hydroxybiphenyl and 70.4 g(510 mmol) of potassium carbonate, 1500 ml of N-methylpyrrolidone wasadded and the resultant solution was stirred at 180° C. for 3 hours.

After completion of the reaction, water was added and extraction bytoluene was conducted. After drying an organic layer over sodiumsulfate, the resultant was condensed. The resultant residue wasre-crystallized through toluene and 44.2 g of 3-bromodibenzofuran in thestate of white crystal was obtained (yield: 60%).

Under the atmosphere of argon gas, 350 ml of toluene and 170 ml of 2 Mconcentration sodium carbonate aqueous solution was added to 34.2 g (138mmol) of 3-bromobenzofram, 26.0 g (166 mmol) of 4-chlorophenyl boronicacid and 3.2 g (2.77 mmol) of tetrakis(triphenylphosphine)palladium (0),and the resultant mixture solution was heated while being refluxed for12 hours.

After the reaction was completed, filtration was carried out immediatelyand a water layer was removed. After drying the organic layer oversodium sulfate, the resultant was concentrated. The residue wassubjected to a chromatography purification using a silica gel column toobtain 23.1 g of white crystal (yield: 60%). The resultant white crystalwas identified as Intermediate 26 from the result in accordance with theFD-MS analysis.

Synthesis Example 27 Synthesis of Intermediate 27

Performing a reaction in the same manner as in Synthesis Example 12except that Intermediate 26 was used instead of 4-bromo-p-terphenyl, 8.5g of a white powder was obtained. The resultant white powder wasidentified as Intermediate 27 from the result in accordance with theFD-MS analysis.

The structural formulae of Compounds H1 to H14 to be produced inExamples-of-Synthesis 1 to 14 each serving as the aromatic aminederivative of the present invention and Comparative Compounds 1 to 4used in Comparative Examples 1 to 4 are as shown below.

Example-of-Synthesis 1 Synthesis of Compound H1

Under an argon gas flow, 6.5 g of Intermediate 5, 9.5 g of Intermediate12, 2.6 g of t-butoxy sodium (manufactured by Hiroshima Wako Co., Ltd.),92 mg of tris(dibenzylideneacetone) dipalladium(0) (manufactured bySIGMA-ALDRICH Corp.), 42 mg of tri-tert-butylphosphine and 100 ml ofdehydrated toluene were placed and the reaction was allowed to proceedat 80° C. for 8 hours.

The resultant solution was cooled down, added with 500 ml of water andfiltered through sellite. The resultant filtrate was extracted withtoluene, and the extract was dried over dehydrated magnesium sulfate.The dried substance was condensed under reduced pressure and the coarseproduct was subjected to column purification. The purified substance wasre-crystallized with a use of toluene and after the resultant crystalwas taken by filtration, the crystal was dried and as a result, 8.1 g ofa pale yellow powder was obtained. The pale yellow powder was identifiedas Compound H1 from the result in accordance with the FD-MS analysis.

Example-of-Synthesis 2 Synthesis of Compound H2

Performing a reaction in the same manner as in Example-of-Synthesis 1except that Intermediate 13 was used instead of Intermediate 12; 7.6 gof a pale yellow powder was obtained. The pale yellow powder wasidentified as Compound H2 from the result in accordance with the FD-MSanalysis.

Example-of-Synthesis 3 Synthesis of Compound H3

Performing a reaction in the same manner as in Example-of-Synthesis 1except that Intermediate 14 was used instead of Intermediate 12; 8.4 gof a pale yellow powder was obtained. The pale yellow powder wasidentified as Compound H3 from the result in accordance with the FD-MSanalysis.

Example-of-Synthesis 4 Synthesis of Compound H4

Performing a reaction in the same manner as in Example-of-Synthesis 1except that Intermediate 15 was used instead of Intermediate 12; 4.6 gof a pale yellow powder was obtained. The pale yellow powder wasidentified as Compound H4 from the result in accordance with the FD-MSanalysis.

Example-of-Synthesis 5 Synthesis of Compound H5

Performing a reaction in the same manner as in Example-of-Synthesis 1except that Intermediate 6 was used instead of Intermediate 5; 8.3 g ofa pale yellow powder was obtained. The pale yellow powder was identifiedas Compound H5 from the result in accordance with the FD-MS analysis.

Example-of-Synthesis 6 Synthesis of Compound H6

Performing a reaction in the same manner as in Example-of-Synthesis 1except that Intermediate 7 was used instead of Intermediate 5; 7.3 g ofa pale yellow powder was obtained. The pale yellow powder was identifiedas Compound H6 from the result in accordance with the FD-MS analysis.

Example-of-Synthesis 7 Synthesis of Compound H7

Performing a reaction in the same manner as in Example-of-Synthesis 1except that 4-bromo-p-terphenyl was used instead of Intermediate 5, andthat Intermediate 16 was used instead of Intermediate 12; 6.5 g of apale yellow powder was obtained. The pale yellow powder was identifiedas Compound H7 from the result in accordance with the FD-MS analysis.

Example-of-Synthesis 8 Synthesis of Compound H8

Performing a reaction in the same manner as in Example-of-Synthesis 1except that Intermediate 9 was used instead of Intermediate 5; 7.9 g ofa pale yellow powder was obtained. The pale yellow powder was identifiedas Compound H8 from the result in accordance with the FD-MS analysis.

Example-of-Synthesis 9 Synthesis of Compound H9

Performing a reaction in the same manner as in Example-of-Synthesis 8except that Intermediate 13 was used instead of Intermediate 12; 7.1 gof a pale yellow powder was obtained. The pale yellow powder wasidentified as Compound H9 from the result in accordance with the FD-MSanalysis.

Example-of-Synthesis 10 Synthesis of Compound H10

Performing a reaction in the same manner as in Example-of-Synthesis 8except that Intermediate 14 was used instead of Intermediate 12; 7.6 gof a pale yellow powder was obtained. The pale yellow powder wasidentified as Compound H10 from the result in accordance with the FD-MSanalysis.

Example-of-Synthesis 11 Synthesis of Compound H11

Performing a reaction in the same manner as in Example-of-Synthesis 8except that Intermediate 15 was used instead of Intermediate 12; 4.9 gof a pale yellow powder was obtained. The pale yellow powder wasidentified as Compound H11 from the result in accordance with the FD-MSanalysis.

Example-of-Synthesis 12 Synthesis of Compound H12

Performing a reaction in the same manner as in Example-of-Synthesis 8except that Intermediate 10 was used instead of Intermediate 9; 5.9 g ofa pale yellow powder was obtained. The pale yellow powder was identifiedas Compound H12 from the result in accordance with the FD-MS analysis.

Example-of-Synthesis 13 Synthesis of Compound H13

Performing a reaction in the same manner as in Example-of-Synthesis 8except that Intermediate 11 was used instead of Intermediate 9; 7.9 g ofa pale yellow powder was obtained. The pale yellow powder was identifiedas Compound H13 from the result in accordance with the FD-MS analysis.

Example-of-Synthesis 14 Synthesis of Compound H14

Performing a reaction in the same manner as in Example-of-Synthesis 8except that 4-bromo-p-terphenyl was used instead of Intermediate 9, andthat Intermediate 17 was used instead of Intermediate 12; 6.1 g of apale yellow powder was obtained. The pale yellow powder was identifiedas Compound H14 from the result in accordance with the FD-MS analysis.

Example-of-Synthesis 15 Synthesis of Compound H15

Performing a reaction in the same manner as in Example-of-Synthesis 1except that Intermediate 18 was used instead of Intermediate 5, 6.9 g ofa pale yellow powder was obtained. The pale yellow powder was identifiedas Compound H15 from the result in accordance with the FD-MS analysis.

Example-of-Synthesis 16 Synthesis of Compound H16

Performing a reaction in the same manner as in Example-of-Synthesis 1except that Intermediate 20 was used instead of Intermediate 5; 7.1 g ofa pale yellow powder was obtained. The pale yellow powder was identifiedas Compound H16 from the result in accordance with the FD-MS analysis.

Example-of-Synthesis 17 Synthesis of Compound H17

Performing a reaction in the same manner as in Example-of-Synthesis 1except that 4-bromo-p-terphenyl was used instead of Intermediate 5, andthat Intermediate 24 was used instead of Intermediate 12; 4.6 g of apale yellow powder was obtained. The pale yellow powder was identifiedas Compound H17 from the result in accordance with the FD-MS analysis.

Example-of-Synthesis 18 Synthesis of Compound H18

Performing a reaction in the same manner as in Example-of-Synthesis 1except that Intermediate 21 was used instead of Intermediate 5; 6.6 g ofa pale yellow powder was obtained. The pale yellow powder was identifiedas Compound H18 from the result in accordance with the FD-MS analysis.

Example-of-Synthesis 19 Synthesis of Compound H19

Performing a reaction in the same manner as in Example-of-Synthesis 1except that Intermediate 23 was used instead of Intermediate 5; 5.1 g ofa pale yellow powder was obtained. The pale yellow powder was identifiedas Compound H19 from the result in accordance with the FD-MS analysis.

Example-of-Synthesis 20 Synthesis of Compound H20

Performing a reaction in the same manner as in Example-of-Synthesis 1except that 4-bromo-p-terphenyl was used instead of Intermediate 5, andthat Intermediate 25 was used instead of Intermediate 12; 4.7 g of apale yellow powder was obtained. The pale yellow powder was identifiedas Compound H20 from the result in accordance with the FD-MS analysis.

Example-of-Synthesis 21 Synthesis of Compound H21

Performing a reaction in the same manner as in Example-of-Synthesis 1except that Intermediate 26 was used instead of Intermediate 5; 5.3 g ofa pale yellow powder was obtained. The pale yellow powder was identifiedas Compound H21 from the result in accordance with the FD-MS analysis.

Example-of-Synthesis 22 Synthesis of Compound H22

Performing a reaction in the same manner as in Example-of-Synthesis 1except that 4-bromo-p-terphenyl was used instead of Intermediate 5, andthat Intermediate 27 was used instead of Intermediate 12; 4.2 g of apale yellow powder was obtained. The pale yellow powder was identifiedas Compound H22 from the result in accordance with the FD-MS analysis.

Constitutional formulae of Compounds H15 to H22 are shown as thefollowing:

Example 1 Production of Organic EL Device

A glass substrate (manufactured by GEOMATEC Company) of 25 mm×75 mm×1.1mm thickness having an ITO transparent electrode was cleaned byapplication of ultrasonic wave in isopropyl alcohol for 5 minutes andthen by exposure to ozone generated by ultraviolet light for 30 minutes.

The cleaned glass substrate having the transparent electrode lines wasattached to a substrate holder of a vacuum vapor deposition apparatus.On the surface of the cleaned substrate at the side having thetransparent electrode, a layer of Compound H1 having a thickness of 80nm was formed so as to cover the transparent electrode. The formed filmworked as a hole injecting and hole transporting layer. Further,Compound EM1 below was vapor deposited thereby forming a film having athickness of 40 nm. At the same time, the following amine compound D1having styryl group below as a light emitting molecule was depositedwith a weight ratio of EM1:D1=40:2. The formed film worked as a lightemitting layer.

On the film formed above, a film of Alq having a thickness of 10 nm wasformed. The formed film worked as an electron injecting layer.Thereafter, Li (the source of lithium: manufactured by SAES GETTERSCompany) as a reductive dopant and Alq were binary vapor deposited andan Alq:Li film (film thickness: 10 nm) was formed as the electroninjecting layer (or a cathode). On the Alq:Li film, aluminum was vapordeposited to form a metal cathode and an organic EL device wasfabricated.

The resultant organic EL device was measured for the emission efficiencyand observed for the luminescent color. The emission efficiency at 10mA/cm² was calculated as current efficiency from the luminance measuredby CS1000 produced by MINOLTA. The half lifetime of emission when drivenby constant DC current at an initial luminance of 5000 cd/m² and roomtemperature was measured. The results are shown in Table 1.

Examples 2 to 14 Pproduction of Organic EL Device

Organic EL devices were fabricated in the same manner as in Example 1except that compounds described in Table 1 were used as the holetransporting material instead of Compound H1.

The organic EL devices were measured for the emission efficiency andobserved from the luminescent color. The half lifetime of emission whendriven by constant DC current at an initial luminance of 5000 cd/m² androom temperature was measured. The results are shown in Table 1.

Comparative Example 1 to 4

Organic EL devices were fabricated in the same manner as in Example 1except that Comparative Compounds 1 (Comparative Example 1) to 4(Comparative Example 4) were used as the hole transporting materialinstead of Compound H1.

The organic EL devices were measured for the emission efficiency andobserved from the luminescent color. The half lifetime of emission whendriven by constant DC current at an initial luminance of 5000 cd/m² androom temperature was measured. The results are shown in Table 1.

Example 15 Production of Organic EL Device

An organic EL device was fabricated in the same manner as in Example 1except that the following arylamine compound D2 was used instead of theamine compound D1 having styryl group. Me in the Compound D2 is a methylgroup.

The organic EL device was measured for the emission efficiency andobserved from the luminescent color. The half lifetime of emission whendriven by constant DC current at an initial luminance of 5000 cd/m² androom temperature was measured. The results are shown in Table 1.

Comparative Example 5

An organic EL device was fabricated in the same manner as in Example 15except that the Comparative Compound 1 was used as the hole transportingmaterial instead of Compound H1.

The organic EL device was measured for the emission efficiency andobserved from the luminescent color. The half lifetime of emission whendriven by constant DC current at an initial luminance of 5000 cd/m² androom temperature was measured. The results are shown in Table 1.

Examples/ Hole- Comparative Transporting Luminescent Half LifetimeExamples Material Color (Hour) Example 1 H1 Blue 460 Example 2 H2 Blue450 Example 3 H3 Blue 390 Example 4 H4 Blue 400 Example 5 H5 Blue 420Example 6 H6 Blue 450 Example 7 H7 Blue 430 Example 8 H8 Blue 450Example 9 H9 Blue 430 Example 10 H10 Blue 400 Example 11 H11 Blue 390Example 12 H12 Blue 410 Example 13 H13 Blue 430 Example 14 H14 Blue 440Example 15 H15 Blue 410 Example 16 H16 Blue 390 Example 17 H19 Blue 400Example 18 H1 Blue 450 Comparative Comparative Blue 130 Example 1Compound 1 Comparative Comparative Blue 160 Example 2 Compound 2Comparative Comparative Blue 90 Example 3 Compound 3 ComparativeComparative Blue 260 Example 4 Compound 4 Comparative Comparative Blue120 Example 5 Compound 1

INDUSTRIAL APPLICABILITY

As described above in detail, molecules in the aromatic amine derivativeof the present invention hardly crystallize; furthermore, an organic ELdevice having a long lifetime can be produced in improved yield byincorporating the derivative into the organic thin film layer of thedevice.

1. An aromatic amine derivative represented by the following generalformula

wherein at least one group among Ar¹ to Ar³ is represented by thefollowing general formula (2):

wherein R¹ and R² each independently represents a substituted orunsubstituted aryl group having the number of carbon atoms of 6 to 50forming the aromatic ring, or a substituted or unsubstituted alkyl grouphaving 1 to 50 carbon atoms respectively; “a” represents an integer of 0to 4, “b” represents an integer of 0 to 3, and “c” represents an integerof 1 to 3; plural R¹'s or R²'s together may be bonded to each other toform a saturated or unsaturated, five- or six-membered ring structurewhich may be substituted; Ar⁴ represents a substituted or unsubstitutedarylene group having the number of carbon atoms of 6 to 50 forming thearomatic ring, or a substituted or unsubstituted fluorenylene group; atleast one group among Ar¹ to Ar³ is represented by the following generalformula (3):

wherein R³ to R⁵ are each independently a substituted or unsubstitutedaryl group having the number of carbon atoms of 6 to 50 forming thearomatic ring, or a substituted or unsubstituted alkyl group having 1 to50 carbon atoms; “e” and “f” each independently represents an integer of0 to 4, “g” represents an integer of 0 to 5; plural R³'s, R⁴'s or R⁵'stogether may be bonded to each other to form a saturated or unsaturated,five- or six-membered ring structure which may be substituted; one ofAr¹ to Ar³ in the general formula (1), which is represented by neitherthe general formula (2) nor the general formula (3) is a substituted orunsubstituted aryl group having the number of carbon atoms of 6 to 50forming the aromatic ring wherein the substituent is an aryl grouphaving the number of carbon atoms of 6 to 50 forming the aromatic ringor an alkyl group having 1 to 50 carbon atoms, with the proviso that itdoes not include the structure of the general formula (3).
 2. Thearomatic amine derivative according to claim 1, wherein Ar⁴ isrepresented by any one of the following general formula (4) or (5):

wherein R⁶'s each independently represents a substituted orunsubstituted aryl group having the number of carbon atoms of 6 to 50forming the aromatic ring, or a substituted or unsubstituted alkyl grouphaving 1 to 50 carbon atoms respectively, “d1” represents an integer of0 to 4, “d2” represents an integer of 0 to 3; and plural R⁶'s on thesame benzene rings or R⁶'s on 2 neighboring benzene rings together maybe bonded to each other to form a saturated or unsaturated, five- orsix-membered ring structure which may be substituted.
 3. The aromaticamine derivative according to claim 1, wherein Ar⁴ is represented by thefollowing general formula (6):

wherein R⁷'s each independently represents a substituted orunsubstituted aryl group having the number of carbon atoms of 6 to 50forming the aromatic ring, or a substituted or unsubstituted alkyl grouphaving 1 to 50 carbon atoms respectively, and “d3” represents an integerof 0 to
 4. 4. The aromatic amine derivative according to claim 1,wherein the above general formula (3) is represented by any one of thefollowing general formula (7), (8) or (9):

wherein R³ to R⁵ and “e” to “g” are the same as those in the abovegeneral formula (3).
 5. The aromatic amine derivative according to claim1, wherein one group among the above Ar¹ to Ar³ is represented by theabove general formula (2); and two groups among the above Ar¹ to Ar³ arerepresented by the above general formula (3).
 6. The aromatic aminederivative according to claim 1, wherein two groups among the above Ar¹to Ar³ are represented by the above general formula (2); and one groupamong the above Ar¹ to Ar³ is represented by the above general formula(3).
 7. The aromatic amine derivative according to claim 1, wherein onegroup among the above Ar¹ to Ar³ is represented by the above generalformula (2); at the same time, Ar⁴ in the above general formula (2) isrepresented by the above general formula (4), (5) or (6), and two groupsamong the above Ar¹ to Ar³ are each represented by any one of the abovegeneral formula (7) or (8) respectively.
 8. The aromatic aminederivative according to claim 1, wherein two groups among the above Ar¹to Ar³ are represented by the above general formula (2); at the sametime, Ar⁴ in the above general formula (2) is represented by the abovegeneral formula (4), (5) or (6), and one group among the above Ar¹ toAr³ is represented by the above general formula (7) or (8).
 9. Thearomatic amine derivative according to claim 1, wherein the abovegeneral formula (2) has a structure represented by the following generalformula (10):

wherein R¹, R², Ar⁴, “a”, “b” and “c” are the same as the abovedefinition.
 10. The aromatic amine derivative according to claim 1,wherein one group among the above Ar¹ to Ar³ is represented by the abovegeneral formula (2); and two groups among the above Ar¹ to Ar³ are eachrepresented by any one of the above general formula (7) or (8)respectively.
 11. The aromatic amine derivative according to claim 1,wherein two groups among the above Ar¹ to Ar³ are represented by theabove general formula (2); and one group among the above Ar¹ to Ar³ isrepresented by the above general formula (7) or (8).
 12. The aromaticamine derivative according to claim 1, wherein the aromatic aminederivative is used as a material for organic electroluminescencedevices.
 13. The aromatic amine derivative according to claim 12,wherein the aromatic amine derivative is used as a hole injectingmaterial or a hole transporting material.
 14. An organicelectroluminescence device which comprises one or more organic thin filmlayers including at least one light emitting layer sandwiched between acathode and an anode, wherein at least one of the organic thin filmlayers comprises the aromatic amine derivative according to claim 1singly or as the mixture component thereof.
 15. The organicelectroluminescence device according to claim 14, wherein the organicthin film layer comprises a hole injecting layer or a hole transportinglayer; and the hole injecting layer or the hole transporting layercomprises the aromatic amine derivative according to claim
 1. 16. Theorganic electroluminescence device according to claim 14, furthercomprising at least one of styrylamine and an arylamine in the lightemitting layer.
 17. The organic electroluminescence device according toclaim 14, which emits blue light.